Energy management for electrified fire fighting vehicle

ABSTRACT

An electrified fire fighting vehicle includes a battery pack, an electromagnetic device, an engine, and a controller. The controller is configured to monitor a state-of-charge of the battery pack, operate the electromagnetic device using stored energy in the battery pack to provide a performance condition including (i) accelerating the electrified fire fighting vehicle to a driving speed of at least 50 miles-per-hour in an acceleration time and (ii) maintaining or exceeding the driving speed for a period of time, and start and operate the engine in response to a start condition to facilitate reserving sufficient stored energy in the battery pack such that the state-of-charge is maintained above a minimum state-of-charge threshold that is sufficient to facilitate the performance condition. The acceleration time is 30 second or less. An aggregate of the acceleration time and the period of time is at least 3 minutes.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.17/066,356, filed Oct. 8, 2020, which claims the benefit of and priorityto (a) U.S. Provisional Patent Application No. 62/914,105, filed Oct.11, 2019, (b) U.S. Provisional Patent Application No. 62/914,109, filedOct. 11, 2019, (c) U.S. Provisional Patent Application No. 62/914,113,filed Oct. 11, 2019, (d) U.S. Provisional Patent Application No.62/914,126, filed Oct. 11, 2019, (e) U.S. Provisional Patent ApplicationNo. 62/914,385, filed Oct. 11, 2019, (f) U.S. Provisional PatentApplication No. 62/970,758, filed Feb. 6, 2020, and (g) U.S. ProvisionalPatent Application No. 63/088,095, filed Oct. 6, 2020, all of which areincorporated herein by reference in their entireties.

BACKGROUND

Fire fighting vehicles such as Aircraft Rescue Fire Fighting (“ARFF”)vehicles are specially designed to respond to airport ground emergencies(e.g., involving an aircraft). Airport ground emergencies may occuranywhere on or near airport property. Water and other agents (e.g., foamfire suppressants) are transported to the emergency site to be appliedand facilitate extinguishment.

SUMMARY

One embodiment relates to a fire fighting vehicle. The fire fightingvehicle includes a chassis, a front axle coupled to the chassis, a rearaxle coupled to the chassis, a powertrain coupled to the chassis, afluid tank coupled to the chassis and configured to store a fluid, apump configured to provide the fluid from the fluid tank to a fluidoutlet, a power divider, and a controller. The powertrain includes anengine, a battery pack, and an electromechanical transmissionelectrically coupled to the battery pack and selectively mechanicallycoupled to the engine. The electromechanical transmission is configuredto (i) generate energy based on a mechanical engine output provided bythe engine, (ii) selectively provide the energy generated to the batterypack for storage as stored energy, and (iii) selectively provide amechanical transmission output to at least one of the front axle or therear axle using at least one of (a) the stored energy in the batterypack or (b) the energy generated based on the mechanical engine output.The power divider is positioned between the engine, the pump, and theelectromechanical transmission. The power divider includes a firstinterface coupled to the engine, a second interface coupled to the pump,and a third interface coupled to the electromechanical transmission. Thecontroller is configured to monitor a state-of-charge of the batterypack and operate the engine, the power divider, and theelectromechanical transmission such that the state-of-charge ismaintained above a minimum state-of-charge threshold that is sufficientto facilitate (i) accelerating the fire fighting vehicle to a drivingspeed of at least 50 miles-per-hour in an acceleration time and (ii)maintaining or exceeding the driving speed for a period of time. Anaggregate of the acceleration time and the period of time is at leastthree minutes.

Another embodiment relates to a fire fighting vehicle. The fire fightingvehicle includes a chassis, a front axle coupled to the chassis, a rearaxle coupled to the chassis, a powertrain coupled to the chassis, and acontroller. The powertrain includes an engine, a battery pack, and anelectromechanical transmission electrically coupled to the battery packand selectively mechanically coupled to the engine. Theelectromechanical transmission is configured to drive at least one ofthe front axle or the rear axle. The controller is configured to monitora state-of-charge of the battery pack and operate the engine and theelectromechanical transmission such that the state-of-charge ismaintained above a minimum state-of-charge threshold that is sufficientto facilitate (i) accelerating the fire fighting vehicle to a drivingspeed of at least 50 miles-per-hour in an acceleration time and (ii)maintaining or exceeding the driving speed for a period of time. Anaggregate of the acceleration time and the period of time is at leastthree minutes.

Still another embodiment relates to a fire fighting vehicle. The firefighting vehicle includes a chassis, a front axle coupled to thechassis, a rear axle coupled to the chassis, a powertrain coupled to thechassis, and a controller. The powertrain includes an engine, a batterypack, and an electromechanical transmission electrically coupled to thebattery pack and selectively mechanically coupled to the engine. Theelectromechanical transmission is configured to drive at least one ofthe front axle or the rear axle. The controller is configured to monitora state-of-charge of the battery pack; monitor a temperature of thebattery pack; monitor a depth-of-discharge of the battery pack duringdischarge events; prevent (i) charging the battery pack above a maximumstate-of-charge threshold that is less than 100% state-of-charge, (ii)prevent the depth-of-discharge from exceeding a depth-of-dischargethreshold, and (iii) prevent the temperature from exceeding atemperature threshold to prevent accelerated degradation of astate-of-health of the battery pack; adaptively reduce the maximumstate-of-charge threshold as the state-of-health of the battery packdegrades; and adaptively adjust the depth-of-discharge threshold suchthat the state-of-charge can be further depleted during subsequentdischarge events as the battery pack degrades.

Still another embodiment relates to a fire fighting vehicle. The firefighting vehicle includes a chassis, a front axle coupled to thechassis, a rear axle coupled to the chassis, a battery pack coupled tothe chassis, and an electromechanical transmission coupled to thechassis and electrically coupled to the battery pack. Theelectromechanical transmission is configured to drive at least one ofthe front axle or the rear axle using stored energy in the battery pack.

Still another embodiment relates to a fire fighting vehicle. The firefighting vehicle includes a chassis; a front axle coupled to thechassis; a rear axle coupled to the chassis; an engine coupled to thechassis; a battery pack coupled to the chassis; an electromechanicaltransmission coupled to the chassis, selectively mechanically coupled tothe engine, and electrically coupled to the battery pack; a pumpconfigured to provide a fluid from a fluid source to a fluid outlet; anda pump driver configured to drive the pump. The electromechanicaltransmission is configured to drive at least one of the front axle orthe rear axle.

Still another embodiment relates to a fire fighting vehicle. The firefighting vehicle includes a chassis; a front axle coupled to thechassis; a rear axle coupled to the chassis; an engine coupled to thechassis; a battery pack coupled to the chassis; an electromechanicaltransmission coupled to the chassis, selectively mechanically coupled tothe engine, and electrically coupled to the battery pack; and a pumpconfigured to provide a fluid from a fluid source to a fluid outlet. Theelectromechanical transmission is configured to drive at least one ofthe front axle or the rear axle. The pump is selectively mechanicallycoupled to the engine and selectively mechanically coupled to theelectromechanical transmission to facilitate pumping the fluid to thefluid outlet.

Still another embodiment relates to a fire fighting vehicle. The firefighting vehicle includes a chassis, a front axle coupled to thechassis, a rear axle coupled to the chassis, a battery pack coupled tothe chassis, an electromechanical transmission electrically coupled tothe battery pack, and a genset coupled to the chassis. The gensetincludes an engine and a generator driven by the engine to produceenergy that is provided to at least one of the battery pack or theelectromechanical transmission. The electromechanical transmission isconfigured to drive at least one of the front axle or the rear axle.

Still another embodiment relates to a fire fighting vehicle. The firefighting vehicle includes a chassis, a battery pack coupled to thechassis, and an electric axle assembly coupled to the chassis. Theelectric axle assembly including an axle, an electric motor electricallycoupled to the battery pack, and a transmission coupled to the axle andthe electric motor. The electric motor is configured to provide amechanical input to the transmission using stored energy in the batterypack. The transmission is configured to provide a mechanical output tothe axle based on the mechanical input.

This summary is illustrative only and is not intended to be in any waylimiting. Other aspects, inventive features, and advantages of thedevices or processes described herein will become apparent in thedetailed description set forth herein, taken in conjunction with theaccompanying figures, wherein like reference numerals refer to likeelements.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a left side view of a fire fighting vehicle having a hybridpowertrain, according to an exemplary embodiment.

FIG. 2 is a right side view of the fire fighting vehicle of FIG. 1 ,according to an exemplary embodiment.

FIG. 3 is a top view of the fire fighting vehicle of FIG. 1 , accordingto an exemplary embodiment.

FIG. 4 is a front view of the fire fighting vehicle of FIG. 1 ,according to an exemplary embodiment.

FIG. 5 is a rear view of the fire fighting vehicle of FIG. 1 , accordingto an exemplary embodiment.

FIG. 6 is a detailed view of various components of a fluid deliverysystem in a left side storage compartment of the fire fighting vehicleof FIG. 1 , according to an exemplary embodiment.

FIG. 7 is a detailed view of various components of the fluid deliverysystem of FIG. 6 in a right side storage compartment of the firefighting vehicle of FIG. 1 , according to an exemplary embodiment.

FIG. 8 is a perspective view of the hybrid powertrain of the firefighting vehicle of FIG. 1 , according to an exemplary embodiment.

FIG. 9 is a side view of the hybrid powertrain of FIG. 8 , according toan exemplary embodiment.

FIG. 10 is a schematic diagram of the hybrid powertrain of FIG. 8 ,according to an exemplary embodiment.

FIG. 11 is a detailed schematic diagram an electromechanical transferdevice of the hybrid powertrain of FIG. 8 , according to an exemplaryembodiment.

FIGS. 12-15 are various views of an accessory drive of the hybridpowertrain of FIG. 8 , according to an exemplary embodiment.

FIG. 16 is schematic diagram of a control system for the fire fightingvehicle of FIG. 1 , according to an exemplary embodiment.

FIG. 17 is a graph presenting example temperature, state-of-health, andstate-of-charge values, according to an exemplary embodiment.

FIG. 18 is a detailed schematic diagram the electromechanical transferdevice of FIG. 11 in an ultra-low mode of operation, according to anexemplary embodiment.

FIG. 19 is a flow diagram of a method for transitioning the hybridpowertrain of FIG. 8 and the fire fighting vehicle of FIG. 1 into andaccording to a standby mode of operation, according to an exemplaryembodiment.

FIG. 20 is a flow diagram of a method for transitioning the hybridpowertrain of FIG. 8 and the fire fighting vehicle of FIG. 1 into andaccording to a rollout mode of operation, according to an exemplaryembodiment.

FIG. 21 is a perspective view of a full electric powertrain, accordingto an exemplary embodiment.

FIG. 22 is a schematic diagram of the full electric powertrain of FIG.15 , according to an exemplary embodiment.

FIGS. 23 and 24 are schematic diagrams of the hybrid powertrain of FIG.8 , according to various other exemplary embodiments.

FIG. 25 is a schematic diagram of the hybrid powertrain of FIG. 8including a generator, according to an exemplary embodiment.

FIG. 26 is a schematic diagram of the hybrid powertrain of FIG. 8 ,according to another exemplary embodiment.

FIG. 27 is a perspective view of the hybrid powertrain of FIG. 26 ,according to an exemplary embodiment.

FIGS. 28 and 29 are section views of the hybrid powertrain of FIG. 27 .

FIGS. 30-34 are perspective views of the hybrid powertrain of FIG. 27 .

FIG. 35 is a schematic diagram of the hybrid powertrain of FIG. 8 ,according to another exemplary embodiment.

DETAILED DESCRIPTION

Before turning to the figures, which illustrate certain exemplaryembodiments in detail, it should be understood that the presentdisclosure is not limited to the details or methodology set forth in thedescription or illustrated in the figures. It should also be understoodthat the terminology used herein is for the purpose of description onlyand should not be regarded as limiting.

Referring generally to the figures, various embodiments of a hybridpowertrain for fire fighting vehicles are shown and described. Firefighting vehicles, for example ARFF vehicles, are specialized vehiclesthat carry water and foam with them to the scene of an emergency.Although the present disclosure specifically references ARFF vehicles,it should be understood that the scope of the present disclosureencompasses any fire fighting vehicle (e.g., a municipal fire fightingvehicle, a quint fire fighting vehicle, a mid-mount fire fightingvehicle, etc.) having a hybrid powertrain. Most commonly, ARFF vehiclesare commissioned for use at an airfield, where the location of anemergency (e.g., an airplane crash, a fire, etc.) can widely vary,thereby prompting the transport of fire fighting materials to theemergency site. ARFF vehicles are heavy duty vehicles in nature and areable to respond at high speeds to reach even remote areas of an airfieldquickly. However, traditional internal combustion driven powertrains arelimited in their response times. A hybrid powertrain (e.g., an at leastpartially electrified powertrain, etc.), on the other hand, can provideimproved acceleration and/or top speeds, thereby reducing response timesand improving fire fighting responsiveness, all while providing a morefuel efficient and eco-friendly solution. As used herein, “hybridpowertrain” means that two separate and distinct power/energy sourcesare used for generating power/energy to operate components of a vehicle.However, “hybrid powertrain” should not be understood to exclusivelyrequire an internal combustion engine and an on-board electric powersource (e.g., a genset, a battery, etc.).

Overall Vehicle

According to the exemplary embodiment shown in FIGS. 1-10 , a fireapparatus, shown as fire fighting vehicle 10, includes a fluid deliveryassembly, shown as fluid delivery system 100, and a powertrain, shown ashybrid powertrain 200. In one embodiment, the hybrid powertrain 200 isconfigured as a diesel/electric hybrid powertrain. In other embodiments,the hybrid powertrain 200 is configured as another type of hybridpowertrain (e.g., gasoline/electric, natural gas/electric, etc.). Instill other embodiments, the fire fighting vehicle 10 does not includethe hybrid powertrain, but rather includes a fully electric powertrain.According to the exemplary embodiment shown in FIGS. 1-5 , the firefighting vehicle 10 is an ARFF vehicle. According to alternativeembodiments, the fire fighting vehicle 10 is a municipal fire fightingvehicle, a quint fire truck, a mid-mount fire truck, an aerial truck, arescue truck, a tanker, or still another type of fire fighting vehicle.According to still other embodiments, the vehicle is another type ofvehicle (e.g., a military vehicle, a commercial vehicle, a refuse truck,a concrete mixer truck, etc.).

As shown in FIGS. 1-5 , the fire fighting vehicle 10 includes a chassis,shown as a frame 12. The frame 12 supports a plurality of tractiveelements, shown as front wheels 14 and rear wheels 16, a body assembly,shown as a rear section 18, and a cab, shown as front cabin 20. In oneembodiment, the fire fighting vehicle 10 is a Striker® 6×6 manufacturedby Oshkosh Corporation® with one front axle to support the front wheels14 and two rear axles to support the rear wheels 16. In otherembodiments, the fire fighting vehicle 10 is a Striker® 4×4, a Striker®1500, a Striker® 3000, or a Striker® 4500 model manufactured by OshkoshCorporation®. Thus, the fire fighting vehicle 10 may include a differentnumber of front axles and/or rear axles to support the front wheels 14and the rear wheels 16 based on the application or model of the firefighting vehicle 10. In an alternative embodiment, the tractive elementsare otherwise structured (e.g., tracks, etc.).

As shown in FIGS. 1-3 , the front cabin 20 is positioned forward of therear section 18 (e.g., with respect to a forward direction of travel forthe vehicle, etc.). According to an alternative embodiment, the frontcabin 20 is positioned behind the rear section 18 (e.g., with respect toa forward direction of travel for the vehicle, etc.). According to anexemplary embodiment, the front cabin 20 includes a plurality of bodypanels coupled to a support (e.g., a structural frame assembly, etc.).The body panels may define a plurality of openings through which anoperator accesses (e.g., for ingress, for egress, to retrieve componentsfrom within, etc.) an interior 24 of the front cabin 20. As shown inFIGS. 1 and 2 , the front cabin 20 includes a pair of doors 22positioned over the plurality of openings defined by the plurality ofbody panels. The doors 22 may provide access to the interior 24 of thefront cabin 20 for a driver (or passengers) of the fire fighting vehicle10. The doors 22 may be hinged, sliding, or bus-style folding doors.

The front cabin 20 may include components arranged in variousconfigurations. Such configurations may vary based on the particularapplication of the fire fighting vehicle 10, customer requirements, orstill other factors. The front cabin 20 may be configured to contain orotherwise support at least one of a number of occupants, storage units,and equipment. As shown in FIGS. 1, 2, and 4 , the front cabin 20 isconfigured to provide seating for an operator (e.g., a driver, etc.) ofthe fire fighting vehicle 10 with a seat, shown as driver seat 26. Insome embodiments, as shown in FIGS. 1-4 , the front cabin 20 isconfigured to provide seating for one or more passengers of the firefighting vehicle 10 with one or more seats, shown as passenger seats 28.The front cabin 20 may include one or more storage areas for providingcompartmental storage for various articles (e.g., supplies,instrumentation, equipment, etc.). The interior 24 of the front cabin 20may further include a user interface. The user interface may include acabin display, a user input device such as a turret joystick, andvarious controls (e.g., buttons, switches, knobs, levers, etc.). In someembodiments, the user interface within the interior 24 of the frontcabin 20 further includes touchscreens, a steering wheel, an acceleratorpedal, a brake pedal, among other components. The user interface mayprovide the operator with control capabilities over the fire fightingvehicle 10 (e.g., direction of travel, speed, etc.), one or morecomponents of hybrid powertrain 200, and/or still other components ofthe fire fighting vehicle 10 from within the front cabin 20.

As shown in FIGS. 1 and 6 , the rear section 18 includes a firstplurality of compartments, shown as left compartments 32, withcorresponding doors, shown as doors 30, disposed along a side (e.g., aleft side, etc.) of the fire fighting vehicle 10. As shown in FIG. 6 ,the doors 30 may be selectively opened to gain access to variouscomponents of the fire fighting vehicle 10 within the left compartments32, including one or more components of the fluid delivery system 100.In other embodiments, the left compartments 32 define a cavity withvarious storage apparatuses (e.g., shelving, hooks, racks, etc.) forequipment (e.g., hoses, extinguishers, ladders, fire fighting gear,etc.).

As shown in FIGS. 2 and 7 , the rear section 18 includes a secondplurality of compartments, shown as right compartments 36, withcorresponding doors, shown as doors 34, disposed along a side (e.g., aright side, etc.) of the fire fighting vehicle 10. As shown in FIGS. 2and 7 , the doors 34 may be selectively opened to gain access to variouscomponents of the fire fighting vehicle 10 within the right compartments36, including one or more components of the fluid delivery system 100,racks, shelving, and/or other storage apparatuses for storing firefighting equipment. As shown in FIGS. 1 and 2 , the rear section 18includes additional compartments with corresponding doors, shown asdoors 38. The doors 38 may be selectively opened to gain access toand/or store various equipment of the fire fighting vehicle 10 (e.g.,hoses, fire fighting gear, etc.) within the additional compartments.

Fluid Delivery System

As shown in FIGS. 1-3 , the fluid delivery system 100 includes a firsttank, shown as water tank 110, and a second tank, shown as agent tank120. The water tank 110 and the agent tank 120 are disposed within therear section 18 of the fire fighting vehicle 10, with the water tank 110positioned above the rear wheels 16 and the agent tank 120 positionedforward of the water tank 110. In other embodiments, the water tank 110and/or the agent tank 120 are otherwise positioned (e.g., disposed alonga rear, front, roof, side, etc. of the fire fighting vehicle 10, etc.).In an alternative embodiment, the fluid delivery system 100 does notinclude at least one of the water tank 110 or the agent tank 120 (e.g.,a municipal fire truck without water storage capabilities that pumpswater from a fire hydrant, etc.). By way of example, the fluid deliverysystem 100 may be configured to utilize an off-vehicle water source(e.g., a fire hydrant, an open body of water, etc.). According to anexemplary embodiment, the water tank 110 and/or the agent tank 120 arecorrosion and UV resistant polypropylene tanks.

According to an exemplary embodiment, the water tank 110 is configuredto store a fluid, such as water or another liquid. In one embodiment(e.g., a 6×6 embodiment, etc.), the water tank 110 is approximately a3,000 gallon capacity tank (e.g., 12,000 liters; 3,170 gallons; 11,350liters; 2,700 gallons; 10,300 liters; at most 3,500 gallons and a least2,500 gallons; etc.). In another embodiment (e.g., a 4×4 embodiment,etc.), the water tank 110 is approximately a 1,500 gallon capacity tank(e.g., 6,000 liters; 1,585 gallons; etc.). In still another embodiment(e.g., an 8×8 embodiment, etc.), the water tank 110 is approximately a4,500 gallon capacity tank (e.g., 17,029 liters; etc.). In otherembodiments, the water tank 110 has another capacity (e.g., a municipalfire truck with a water tank having at least a 200 gallon capacity andapproximately between a 200 and a 400 gallon capacity, such as, forexample, 300 gallons, etc.). In some embodiments, multiple water tanks110 are disposed within and/or along the rear section 18 of the firefighting vehicle 10.

According to an exemplary embodiment, the agent tank 120 is configuredto store an agent, such as a foam fire suppressant. According to anexemplary embodiment, the agent is an aqueous film forming foam(“AFFF”). AFFF is water-based and frequently includes hydrocarbon-basedsurfactant (e.g., sodium alkyl sulfate, etc.) and a fluorosurfactant(e.g., fluorotelomers, perfluorooctanoic acid, perfluorooctanesulfonicacid, etc.). AFFF has a low viscosity and spreads rapidly across thesurface of hydrocarbon fuel fires. An aqueous film forms beneath thefoam on the fuel surface that cools burning fuel and preventsevaporation of flammable vapors and re-ignition of fuel once it has beenextinguished. The film also has a self-healing capability whereby holesin the film layer are rapidly resealed. In alternative embodiments,another agent is stored with the agent tank 120 (e.g., low-expansionfoams, medium-expansion foams, high-expansion foams, alcohol-resistantfoams, synthetic foams, protein-based foams, foams to be developed,fluorine-free foams, film-forming fluoro protein (“FFFP”) foams, alcoholresistant aqueous film forming foam (“AR-AFFF”), etc.). In oneembodiment, the agent tank 120 is approximately a 420 gallon capacitytank. In another embodiment, the agent tank 120 is approximately a 210gallon capacity tank. In still another embodiment, the agent tank 120 isapproximately a 540 gallon capacity tank. In other embodiments, theagent tank 120 has another capacity. In some embodiments, multiple agenttanks 120 are disposed within or along the rear section 18 of the firefighting vehicle 10. The capacity of the water tank 110 and/or the agenttank 120 may be specified by a customer. It should be understood thatwater tank 110 and the agent tank 120 configurations are highlycustomizable, and the scope of the present disclosure is not limited toparticular size or configuration of the water tank 110 and the agenttank 120. As shown in FIGS. 1 and 2 , the fire fighting vehicle 10includes one or more indicators, shown as fluid level indicators 102.The fluid level indicators 102 may be configured to provide anindication of the amount of water and/or agent within the water tanks110 and/or the agent tank 120, respectively.

As shown is FIGS. 6 and 7 , the water tank 110 includes a plurality ofconduits, shown as water fill lines 116, that extend therefrom to aplurality of inlets, shown as water inlets 118. The water fill lines 116fluidly couple the water inlets 118 to the water tank 110 such that thewater tank 110 may be refilled with water (e.g., from a pumping station,from a fire hydrant, from a water truck, etc.) with the water inlets118. As shown in FIGS. 6 and 7 , the water inlets 118 are positionedwithin the left compartments 32 and the right compartments 36. In otherembodiments, the water inlets 118 are otherwise positioned (e.g., extendoutward from the rear section 18, disposed along an exterior of the firefighting vehicle 10, etc.). According to an exemplary embodiment, thewater inlets 118 include a 2.5 inch diameter inlet and a 4.5 inchdiameter inlet (e.g., to facilitate various connections between a watersource, etc.). In other embodiments, one or more of the water inlets 118are differently sized.

As shown is FIGS. 6 and 7 , the agent tank 120 includes a plurality ofconduits, shown as agent fill lines 126, that extend therefrom to aplurality of inlets, shown as agent inlets 128. The agent fill lines 126fluidly couple the agent inlets 128 to the agent tank 120 such that theagent tank 120 may be refilled with agent (e.g., from a pumping station,etc.) with the agent inlets 128. As shown in FIGS. 6 and 7 , the agentinlets 128 are positioned along a bottom edge of the rear section 18 oneach lateral side of the fire fighting vehicle 10. In other embodiments,the agent inlets 128 are otherwise positioned (e.g., within the leftcompartments 32 and/or the right compartments 36, etc.). According to anexemplary embodiment, the agent inlets 128 include a 1.5 inch diameterinlet. In other embodiments, one or more of the agent inlets 128 aredifferently sized (e.g., a 2.5 inch diameter inlet, etc.).

As shown in FIGS. 6 and 8-10 , the fluid delivery system 100 includes afluid driving system, shown as pump system 140. According to anexemplary embodiment, the pump system 140 includes a single, highpressure pump. In one embodiment, the high pressure pump isapproximately a 400 horsepower (“hp”) pump (e.g., between 350 hp and 450hp, etc.). In another embodiment, the pump system 140 includes a lowerpressure pump (e.g., operates at less than 400 hp (e.g., 50 hp, 100 hp,150 hp, 200 hp, 250 hp, 300 hp, etc.). In other embodiments, the pumpsystem 140 includes a first, low pressure pump arranged in a seriesconfiguration with a second, high pressure pump. According to anexemplary embodiment, providing pre-pressurized fluid to the second pumpfrom the first pump reduces (e.g., eliminates, etc.) priming issues ofthe second pump, increases the output pressure capabilities of thesecond pump, reduces the power output and/or torque output needed fromthe hybrid powertrain 200 or other pump driver to drive the second pumpto reach higher pressures, reduces (e.g., eliminates, etc.) cavitationat the inlet of the second pump, and/or decreases the overall size ofthe second pump (e.g., increasing available space and serviceability ofthe fluid delivery system 100, etc.). Further details regarding such atwo pump system may be found in U.S. Patent Publication No.2017/0050063, filed Aug. 17, 2016, which is incorporated herein byreference in its entirety.

As shown in FIGS. 1-4, 6, and 7 , the fluid delivery system 100 includesa first discharge, shown as structural discharge 170, a seconddischarge, shown as turret 180, and a third discharge, shown as hosereel 190. In some embodiments, the fluid delivery system 100 includes asecond turret. In some embodiments, the fluid delivery system 100additionally or alternatively includes a high reach extendible turret(“HRET”). According to an exemplary embodiment, the pump system 140 isconfigured to pump the water from the water tank 110 and/or the agentfrom the agent tank 120, pressurize the water, mix the agent with thewater (if agent is being used), and provide the pressurized water and/orwater-agent mixture to one or more of the structural discharge 170, theturret 180, and the hose reel 190. In some embodiments, the pump system140 is additionally or alternatively configured to pump water from anexternal, off-vehicle source (e.g., a fire hydrant, an open body ofwater, etc.). In some embodiments, (i) the structural discharge 170receives pressurized water and/or pressure water-agent mixture from thepump system 140 at a first pressure (e.g., 170 psi, etc.) and (ii) theturret 180 and/or the hose reel 190 receive pressurized water and/orpressurized water-agent mixture from the pump system 140 at a secondpressure (e.g., between 1000 psi and 1500 psi, etc.) that is greaterthan the first pressure. According to an exemplary embodiment, thesubstantially higher pressure causes the turret 180 and/or the hose reel190 to create smaller water and/or agent droplets, thereby increasingthe surface area of the fluid being expelled by the fluid deliverysystem 100 relative to traditional systems. Increased surface area ofthe fluid may thereby increase the rate at which heat transfer occurssuch that the fluid delivery system 100 has a higher fire fightingcapability (e.g., relative to traditional systems, etc.).

As shown in FIGS. 6 and 7 , the structural discharge 170 includes aplurality of outlets, shown as low pressure outlets 172. As shown inFIGS. 6 and 7 , the low pressure outlets 172 are positioned within theleft compartments 32 and the right compartments 36. In otherembodiments, the low pressure outlets 172 are otherwise positioned(e.g., extend outward from the rear section 18, disposed along anexterior of the fire fighting vehicle 10, etc.). According to anexemplary embodiment, the low pressure outlets 172 include a 2.5 inchdiameter outlet. In other embodiments, one or more of the low pressureoutlets 172 are differently sized. According to an exemplary embodiment,the low pressure outlets 172 are configured to engage a hose during astructural mode of operation (e.g., low pressure mode, etc.) of thefluid delivery system 100 such that the fluid (e.g., water and/or agent,etc.) pumped via the pump system 140 to the structural discharge 170 maybe applied to a fire at a low pressure (e.g., 170 psi, etc.).

As shown in FIGS. 1-4 , the turret 180 is positioned on a front bumperof the fire fighting vehicle 10. In other embodiments, the turret 180 isotherwise positioned (e.g., attached to a boom, on the roof, on the rearsection 18, etc.). In some embodiments, the fire fighting vehicle 10includes a plurality of turrets 180 (e.g., a bumper turret and a roofturret, etc.). According to an exemplary embodiment, the turret 180 iscontrolled via a user interface (e.g., a joystick, etc.) located withinthe interior of the front cabin 20. In some embodiments, the turret 180can be manually operated (e.g., during a fault condition, etc.).According to an exemplary embodiment, the pump system 140 is configuredto provide the fluid (e.g., water, water-agent mixture, etc.) to theturret 180 at a target pressure of approximately 1250 psi and a targetflow rate of at least 300 gpm. In some embodiments, the pump system 140provides the fluid to the turret 180 at a different pressure and/or flowrate (e.g., 315 gpm, 310 gpm, 1300 psi, based on the use of the hosereel 190, etc.).

As shown in FIG. 6 , the hose reel 190 is positioned within one of theleft compartments 32. In other embodiments, the hose reel 190 isotherwise positioned (e.g., within the right compartments 36, on theroof of the fire fighting vehicle 10, etc.). In some embodiments, thefire fighting vehicle 10 includes a plurality of hose reels 190 (e.g.,one on each lateral side of the fire fighting vehicle 10, etc.).According to an exemplary embodiment, the pump system 140 is configuredto provide the fluid (e.g., water, water-agent mixture, etc.) to thehose reel 190 at a target pressure of 1100 psi and a target flow rate of20 gpm. In some embodiments, the pump system 140 provides the fluid tothe hose reel 190 at a different pressure and/or flow rate (e.g., 25gpm, 1000 psi, etc.).

Hybrid Powertrain

As shown in FIGS. 8-10 , the hybrid powertrain 200 of the fire fightingvehicle 10 includes (i) a first driver, shown as engine 210, having afirst interface, shown as power divider interface 212; (ii) a powersplitting mechanism, shown as power divider 220, having (a) a secondinterface, shown engine interface 222, (b) a third interface, shown aspump interface 224, and (c) a fourth interface, shown aselectromechanical transfer device (“ETD”) interface 226; (iii) a seconddriver (e.g., an electromechanical transmission, etc.), shown as ETD240, having (a) a fifth interface, shown as power divider interface 242,(b) a sixth interface, shown as front axle interface 244, and (c) aseventh interface, shown as rear axle interface 246; (iv) an on-boardelectric power source, shown as battery pack 260; and (v) an auxiliarydrive, shown as accessory drive 270.

As shown in FIGS. 8 and 9 , the engine 210 is coupled to the frame 12 ata rear end thereof and at least partially behind the rear wheels 16(i.e., the rear axle(s)). In other embodiments, the engine 210 isotherwise positioned (e.g., at a front end of the frame 12, forward ofthe front axle, between the front axle(s) and the rear axle(s), etc.).According to an exemplary embodiment, the engine 210 is acompression-ignition internal combustion engine that utilizes dieselfuel. In alternative embodiments, the engine 210 is another type ofdriver (e.g., spark-ignition engine, fuel cell, electric motor, etc.)that is otherwise powered (e.g., with gasoline, compressed natural gas,propane, hydrogen, electricity, etc.). According to an exemplaryembodiment, the engine 210 is capable of outputting approximately 400kilowatts (“kW”) or 550 hp. In other embodiments, the engine 210 is asmaller or a larger engine that provides lesser or greater power output(e.g., less than 900 hp, less than 800 hp, less than 750 hp, less than700 hp, less than less than 650 hp, between 500 and 600 hp, etc.)depending on the sizing of other components in the hybrid powertrain 200and/or customer specifications.

As shown in FIG. 9 , the battery pack 260 is coupled to the frame 12 viaa bracket/housing, shown as battery housing 262. According to theexemplary embodiment shown in FIG. 9 , the battery housing 262 positionsthe battery pack 260 forward of the engine 210, above the power divider220, and rearward of at least one (e.g., both, only one, etc.) rear axle(and rearward of the water tank 110). In other embodiments, the batterypack 260 is otherwise positioned (e.g., at the front end of the frame12, above or proximate the ETD 240, behind the engine 210, forward ofthe water tank 110, etc.).

As shown in FIG. 10 , the battery pack 260 is electrically coupled tothe ETD 240. According to an exemplary embodiment, the battery pack 260is configured to provide electrical energy to the ETD 240 to facilitateor supplement operation thereof and/or receive electrical energygenerated by the ETD 240 to charge the battery pack 260 (e.g., based ona mode of operation of the fire fighting vehicle 10, etc.). Accordingly,the battery pack 260 may be charged from an external power station orinput, the ETD 240, a regenerative braking system, and/or other suitableelectrical energy sources. According to an exemplary embodiment, thebattery pack 260 includes a plurality of battery cells that provide abattery capacity capable of providing approximately 28 kilowatt hours(“kWh”) of energy. In other embodiments, the battery pack 260 is less ormore battery capacity to provide a lesser or a greater amount of energy(e.g., between 20 and 40 kWh, less than 60 kWh, less than 50 kWh,between 12 kWh and 60 kWh, etc.). In some embodiments, the battery pack260 has a larger capacity (e.g., 80 hWh, 100 kWh, 150 kWh, 200 kWh,etc.) and the size and power output of the engine 210 may be reduced.Alternatively, in a fully electric powertrain, the battery pack 260 mayprovide a battery capacity capable of providing up to or exceeding 330kWh. In such an embodiment, the battery pack 260 may replace and bepositioned in the location of the engine 210. In some embodiments, thebattery pack 260 includes a set of two or more batteries in a series orparallel arrangement depending on electrical needs of the hybridpowertrain 200. The battery pack 260 can be located in various locationsof the fire fighting vehicle 10 to achieve a desired packaging, weightbalance, or cost performance of the hybrid powertrain 200 and the firefighting vehicle 10.

As shown in FIGS. 8-10 , the power divider 220 is coupled to the frame12 and positioned between the engine 210, the pump system 140, and theETD 240. As shown in FIG. 9 , the power divider interface 212 of theengine 210 and the engine interface 222 of the power divider 220 are indirect engagement such that the power divider 220 is directly driven bythe engine 210. In other embodiments, the power divider interface 212 ofthe engine 210 and engine interface 222 of the power divider 220 arecoupled together by an intermediate member (e.g., a connecting shaft, agearbox, a clutch, a continuous variable transmission, a pulley, etc.).

As shown in FIGS. 8-10 , the pump interface 224 of the power divider 220is mechanically coupled to an eighth interface, shown as power dividerinterface 142, of the pump system 140 via a first connecting shaft,shown as pump shaft 228. In other embodiments, the pump interface 224 ofthe power divider 220 and the power divider interface 142 of the pumpsystem 140 are in direct engagement. In still other embodiments, thepump interface 224 of the power divider 220 and the power dividerinterface 142 of the pump system 140 are otherwise coupled (e.g., via agearbox, a pulley, etc.).

As shown in FIGS. 8-10 , the ETD interface 226 of the power divider 220is mechanically coupled to the power divider interface 242 of the ETD240 via a second connecting shaft, shown as ETD shaft 230. In otherembodiments, the ETD interface 226 of the power divider 220 and thepower divider interface 242 of the ETD 240 are in direct engagement. Instill other embodiments, the ETD interface 226 of the power divider 220and the power divider interface 242 of the ETD 240 are otherwise coupled(e.g., via a pulley, etc.).

According to an exemplary embodiment, the power divider 220 isconfigured to facilitate selectively, mechanically coupling (i) theengine 210 to the pump system 140 and (ii) the engine 210 to the ETD240. As shown in FIG. 10 , the power divider 220 includes a firstclutch, shown as pump clutch 232, positioned between the engineinterface 222 and the pump interface 224. According to an exemplaryembodiment, the pump clutch 232 is positioned to facilitate selectively,mechanically coupling the engine 210 to the pump system 140 (e.g., basedon the mode of operation of the fire fighting vehicle 10, etc.) tofacilitate pumping fluid from the water tank 110, the agent tank 120,and/or an off-vehicle water source to a fluid outlet of the firefighting vehicle 10 (e.g., the structural discharge 170, the turret 180,the hose reel 190, etc.). According to an exemplary embodiment, theengine 210 drives the pump system 140 through the power divider 220 andthe pump shaft 228 at a certain (e.g., fixed, etc.) ratio. In analternative embodiment, the pump system 140 or the pump shaft 228 aredirectly coupled to a power-take-off (“PTO”) of the engine 210. Inanother alternative embodiment, the pump system 140 or the pump shaft228 are directly coupled to a PTO of the ETD 240.

As shown in FIG. 10 , the power divider 220 includes a second clutch,shown as ETD clutch 234, positioned between the engine interface 222 andthe ETD interface 226. According to an exemplary embodiment, the ETDclutch 234 is positioned to facilitate selectively, mechanicallycoupling the engine 210 to the ETD 240 (e.g., based on the mode ofoperation of the fire fighting vehicle 10, etc.) to facilitate drivingcomponents of the ETD 240, as described in further detail herein. In analternative embodiment, the power divider 220 does not include the ETDclutch 234. By way of example, the power divider 220 may alternativelyhave a through-shaft design such that an output of the engine 210connects to an input of the ETD 240 without a clutch positionedtherebetween. In such an embodiment, the power divider 220 may include agear train assembly coupled between the output of the engine 210 and thepump clutch 232. In some embodiments, a clutch is positioned between (i)the engine 210 and (ii) the power divider 220 and the ETD 240 such thatthe engine 210 can be selectively decoupled from the rest of the hybridpowertrain 200. In some embodiments, a clutch is positioned between (i)the power divider 220 and (ii) the ETD 240 such that the ETD 240 can beselectively decoupled from the engine 210 and the power divider 220.

As shown in FIGS. 8 and 9 , the ETD 240 is coupled to the frame 12 andpositioned (i) forward of the engine 210, the power divider 220, and therear wheels 16 (i.e., the rear axle(s)) and (ii) rearward of the frontwheels 14 (i.e., the front axle(s)). In other embodiments, the ETD 240is otherwise positioned (e.g., rearward of the engine 210 and the powerdivider 220, etc.).

As shown in FIGS. 9 and 10 , the front axle interface 244 of the ETD 240is mechanically coupled to a first or front differential of a firstaxle, shown as front axle 252, to which the front wheels 14 areconnected, via a third connecting shaft, shows as front drive shaft 248.In some embodiments, the front axle 252 is a tandem front axle. As shownin FIGS. 9 and 10 , the rear axle interface 246 of the ETD 240 ismechanically coupled to a second or rear differential of one or morerear axles (e.g., a single rear axle, a tandem rear axle, etc.), shownas rear axles 254, to which the rear wheels 16 are connected, via afourth connecting shaft, shown as rear drive shaft 250. In someembodiments, the hybrid powertrain 200 does not include one of the frontdrive shaft 248 or the rear drive shaft 250 and/or the ETD 240 does notinclude one of the front axle interface 244 or the rear axle interface246. (e.g., a rear wheel drive embodiment, a front wheel driveembodiment, etc.). In some embodiments, the ETD 240 does not includeeither of the front axle interface 244 or the rear axle interface 246.Rather, the hybrid powertrain 200 may include a transfer case positionedexternally relative to and coupled to the ETD 240 (e.g., the ETD 240 hasa single, transfer case output, etc.), and the transfer case may includethe front axle interface 244 and the rear axle interface 246. Accordingto an exemplary embodiment, the ETD 240 is (i) selectively, mechanicallycoupled to the engine 210 by the power divider 220 and (ii) electricallycoupled to battery pack 260 to facilitate (a) selectively driving thefront axle(s) 252 and/or the rear axle(s) 254 (e.g., directly,indirectly through the external transfer case, etc.) and (b) selectivelycharging the battery pack 260. In an alternative embodiment, the ETD 240in not configured to charge the battery pack 260 (e.g., the battery pack260 is chargeable through a charging station, regenerative braking,etc.).

According to an exemplary embodiment, the ETD 240 is anelectromechanical infinitely variable transmission (“EMIVT”) thatincludes a first electromagnetic device (e.g., a first motor/generator,etc.) and a second electromagnetic device (e.g. a secondmotor/generator, etc.) coupled to each other via a plurality of gearsets (e.g., planetary gear sets, etc.). The EMIVT also includes one ormore brakes and one or more clutches to facilitate operation of theEMIVT in various modes (e.g., a drive mode, a battery charging mode, alow-range speed mode, a high-range speed mode, a reverse mode, anultra-low mode, etc.). In some implementations, all of such componentsmay be efficiently packaged in a single housing with only the inputs andoutputs exposed. By way of example, the first electromagnetic device maybe driven by the engine 210 to generate electricity. The electricitygenerated by the first electromagnetic device may be used (i) to chargethe battery pack 260 and/or (ii) to power the second electromagneticdevice to drive the front axle(s) 252 and/or the rear axle(s) 254. Byway of another example, the second electromagnetic device may be drivenby the engine 210 to generate electricity. The electricity generated bythe second electromagnetic device may be used (i) to charge the batterypack 260 and/or (ii) to power the first electromagnetic device to drivethe front axle(s) 252 and/or the rear axle(s) 254. By way of anotherexample, the first electromagnetic device and/or the secondelectromagnetic device may be powered by the battery pack 260 to (i)back-start the engine 210 (e.g., such that an engine starter is notnecessary, etc.), (ii) drive the accessory drive 270 (e.g., when theengine 210 is off, when the ETD clutch 234 is disengaged, etc.), and/or(iii) drive the front axle(s) 252 and/or the rear axle(s) 254. By way ofyet another example, the first electromagnetic device may be driven bythe engine 210 to generate electricity and the second electromagneticdevice may receive both the generated electricity from the firstelectromagnetic device and the stored energy in the battery pack 260 todrive the front axle(s) 252 and/or the rear axle(s) 254. By way of yetstill another example, the second electromagnetic device may be drivenby the engine 210 to generate electricity and the first electromagneticdevice may receive both the generated electricity from the secondelectromagnetic device and the stored energy in the battery pack 260 todrive the front axle(s) 252 and/or the rear axle(s) 254. Further detailsregarding the components of the EMIVT and the structure, arrangement,and functionality thereof may be found in (i) U.S. Pat. No. 8,337,352,filed Jun. 22, 2010, (ii) U.S. Pat. No. 9,651,120, filed Feb. 17, 2015,(iii) U.S. Pat. No. 10,421,350, filed Oct. 20, 2015, (iv) U.S. PatentPublication No. 2017/0363180, filed Aug. 31, 2017, (v) U.S. PatentPublication No. 2017/0370446, filed Sep. 7, 2017, (vi) U.S. Pat. No.10,578,195, filed Oct. 4, 2017, and (vii) U.S. Patent Publication No.2019/0178350, filed Feb. 17, 2019, all of which are incorporated hereinby reference in their entireties. In other embodiments, the ETD 240includes a device or devices different than the EMIVT (e.g., anelectronic transmission, a motor coupled to a transfercase, etc.).

Referring to FIG. 11 , an example of the ETD 240 is shown according toan exemplary embodiment. In this embodiment, the ETD 240 is an EMIVT. Asshown in FIG. 11 , the ETD 240 includes a mechanical power transmissionassembly (e.g., gearbox, gear set, gear train, mechanical transmissionassembly, etc.), shown as transmission 330, a first electromagneticdevice, shown as first motor/generator 340, a second motor/generator350, shown as second motor/generator 350, the power divider interface242, the front axle interface 244, and the rear axle interface 246. Thetransmission 330 includes a first gear set, shown as power splitplanetary 410, and a second gear set, shown as output planetary 420. Inone embodiment, the power split planetary 410 and the output planetary420 are disposed between the first motor/generator 340 and the secondmotor/generator 350. In an alternative embodiment, one or both of thepower split planetary 410 and the output planetary 420 are positionedoutside of (i.e., not between) the first motor/generator 340 and thesecond motor/generator 350. As shown in FIG. 11 , the power splitplanetary 410 is directly coupled to the power divider interface 242.

As shown in FIG. 11 , the power split planetary 410 is a planetary gearset that includes a sun gear 412, a ring gear 414, and a plurality ofplanetary gears 416. The plurality of planetary gears 416 couple the sungear 412 to the ring gear 414. As shown in FIG. 11 , a carrier 418rotationally supports the plurality of planetary gears 416. In oneembodiment, the first motor/generator 340 is directly coupled to the sungear 412 such that the power split planetary 410 is coupled to the firstmotor/generator 340. By way of example, the first motor/generator 340may include a shaft (e.g., a first shaft, an input shaft, an outputshaft, etc.) directly coupled to the sun gear 412.

As shown in FIG. 11 , the output planetary 420 is a planetary gear setthat includes a sun gear 422, a ring gear 424, and a plurality ofplanetary gears 426. The plurality of planetary gears 426 couple the sungear 422 to the ring gear 424. As shown in FIG. 11 , a carrier 428rotationally supports the plurality of planetary gears 426. In oneembodiment, the second motor/generator 350 is directly coupled to thesun gear 422 such that the output planetary 420 is coupled to the secondmotor/generator 350. By way of example, the second motor/generator 350may include a shaft (e.g., a second shaft, an input shaft, an outputshaft, etc.) directly coupled to the sun gear 422. The carrier 418 isdirectly coupled to the carrier 428, thereby coupling the power splitplanetary 410 to the output planetary 420, according to the exemplaryembodiment shown in FIG. 11 . In one embodiment, directly coupling thecarrier 418 to the carrier 428 synchronizes rotational speeds of thecarrier 418 and the carrier 428.

As shown in FIG. 11 , the transmission 330 includes a first clutch,shown as power split coupled clutch 430. In one embodiment, the powersplit coupled clutch 430 is positioned downstream of the power splitplanetary 410 (e.g., between the power split planetary 410 and the frontaxle interface 244 or the rear axle interface 246, etc.). As shown inFIG. 11 , the power split coupled clutch 430 is positioned toselectively couple the power split planetary 410 and the outputplanetary 420 with a shaft, shown as output shaft 332. In oneembodiment, the power split coupled clutch 430 allows a vehicle to betowed without spinning the gears within the transmission 330 (e.g., thepower split planetary 410, the output planetary 420, etc.). The outputshaft 332 may be coupled to the rear axle interface 246 and selectivelycoupled to front axle interface 244 with a declutch assembly, shown asthe front declutch collar shift 334. The front declutch collar shift 334may be engaged and disengaged to selectively couple the front axleinterface 244 to the output shaft 332 of the transmission 330 (e.g., tofacilitate operation of a vehicle in a rear-wheel-drive-only mode, anall-wheel-drive mode, a four-wheel-drive mode, etc.).

As shown in FIG. 11 , the transmission 330 includes a second clutch,shown as input coupled clutch 440. The input coupled clutch 440 ispositioned to selectively couple the second motor/generator 350 with thepower divider interface 242, according to an exemplary embodiment. Theinput coupled clutch 440 may thereby selectively couple the powerdivider interface 242 to the output planetary 420. As shown in FIG. 11 ,the transmission 330 includes a shaft, shown as the connecting shaft336. The connecting shaft 336 extends from the power divider interface242, through the second motor/generator 350, and through the outputplanetary 420 to the power split planetary 410. The connecting shaft 336couples the power divider interface 242 with the power split planetary410, according to the exemplary embodiment shown in FIG. 11 . In oneembodiment, the connecting shaft 336 directly couples the power dividerinterface 242 with the ring gear 414 of the power split planetary 410.The input coupled clutch 440 may selectively couple the secondmotor/generator 350 with the connecting shaft 336. According to anexemplary embodiment, the shaft (e.g., input/output shaft, etc.) of thefirst motor/generator 340 and the shaft (e.g., input/output shaft, etc.)of the second motor/generator 350 are radially aligned with the powersplit planetary 410, the output planetary 420, and the connecting shaft336 (e.g., centerlines thereof are aligned, etc.). As shown in FIG. 11 ,the transmission 330 includes a third clutch, shown as output coupledclutch 450. The output coupled clutch 450 is positioned to selectivelycouple the output planetary 420 with the output shaft 332. In oneembodiment, the output shaft 332 is radially offset from the power splitplanetary 410, the output planetary 420, and the connecting shaft 336(e.g., radially offset from centerlines thereof, etc.).

As shown in FIG. 11 , the transmission 330 includes a first brake, shownas power split brake 460. The power split brake 460 is positioned toselectively inhibit the movement of at least a portion of the powersplit planetary 410 (e.g., the planetary gears 416, the carrier 418,etc.) and the output planetary 420 (e.g., the planetary gears 426, thecarrier 428, etc.). In other embodiments, the transmission 330 does notinclude the power split brake 460. The power split brake 460 may therebybe an optional component of the transmission 330. As shown in FIG. 11 ,the transmission 330 includes a second brake (or a first brake inembodiments where the transmission 330 does not include the power splitbrake 460), shown as the output brake 470. The output brake 470 ispositioned to selectively inhibit the movement of at least a portion ofthe output planetary 420 (e.g., the ring gear 424, etc.). In oneembodiment, at least one of the power split brake 460 and the outputbrake 470 are biased into an engaged position (e.g., with a spring,etc.) and selectively disengaged (e.g., with application of pressurizedhydraulic fluid, etc.). In other embodiments, the power split brake 460and the output brake 470 are hydraulically-biased and spring released.In still other embodiments, the components of the transmission 330 arestill otherwise engaged and disengaged (e.g., pneumatically, etc.). Byway of example, the output brake 470 and the output coupled clutch 450may be engaged simultaneously to function as a driveline brake (e.g., abraking mechanism to slow down a vehicle, etc.). By way of anotherexample, the power split brake 460 and the power split coupled clutch430 may be engaged simultaneously to function as a driveline brake. Inother embodiments, one or both of the power split brake 460 and theoutput brake 470 are omitted from the ETD 240.

As shown in FIG. 11 , the transmission 330 includes a first gear set,shown as gear set 480, that couples the carrier 418 and the carrier 428to the output shaft 332. The gear set 480 includes a first gear, shownas gear 482, in meshing engagement with a second gear, shown as gear484. As shown in FIG. 11 , the gear 482 is rotatably coupled to thecarrier 418 and the carrier 428. By way of example, the gear 482 may befixed to a component (e.g., shaft, tube, etc.) that couples the carrier418 and the carrier 428. As shown in FIG. 11 , the power split coupledclutch 430 is positioned to selectively couple the gear 484 with theoutput shaft 332 when engaged. With the power split coupled clutch 430disengaged, relative movement (e.g., rotation, etc.) may occur betweenthe gear 484 and the output shaft 332. The power split brake 460 may bepositioned to selectively limit the movement of the gear 484 whenengaged to thereby limit the movement of the gear 482, the carrier 418,and the carrier 428.

As shown in FIG. 11 , the transmission 330 includes a second gear set,shown as the gear set 490, that couples the output planetary 420 to theoutput shaft 332. The gear set 490 includes a first gear, shown as gear492, coupled to the ring gear 424 of the output planetary 420. The gear492 is in meshing engagement with a second gear, shown as gear 494. Thegear 494 is coupled to a third gear, shown as gear 496. In otherembodiments, the gear 492 is directly coupled with the gear 496. By wayof example, the gear set 490 may not include the gear 494, and the gear492 may be directly coupled to (e.g., in meshing engagement with, etc.)the gear 496. As shown in FIG. 11 , the output coupled clutch 450 ispositioned to selectively couple the gear 496 with the output shaft 332when engaged. With the output coupled clutch 450 disengaged, relativemovement (e.g., rotation, etc.) may occur between the gear 496 and theoutput shaft 332. By way of example, the output coupled clutch 450 maybe engaged to couple the ring gear 424 to the output shaft 332. Theoutput brake 470 is positioned to selectively limit the movement of thegear 492 when engaged to thereby also limit the movement of the ringgear 424, the gear 494, and the gear 496.

As shown in FIGS. 10 and 12 , the accessory drive 270 (e.g., anaccessory module) includes a base or frame, shown as accessory base 272,coupled to the power divider 220 (e.g., a housing thereof, etc.) and apulley assembly, shown as accessory pulley assembly 274, coupled to(e.g., supported by, extending from, etc.) the accessory base 272 anddriven by ETD interface 226 of the power divider 220. As shown in FIGS.10 and 12-15 , the accessory pulley assembly 274 includes a plurality ofpulleys, shown as accessory pulleys 276, coupled to the accessory base272; a belt, shown as accessory belt 278; and an input pulley, shown asdrive pulley 280, coupled to (i) the ETD interface 226 of the powerdivider 220 and (ii) the accessory pulleys 276 by the accessory belt278. Accordingly, the ETD interface 226 is configured (e.g., positioned,etc.) to drive the drive pulley 280 and, thereby, the accessory pulleys276 to drive various accessories, shown as vehicle accessories 290, ofthe accessory drive 270. As shown in FIGS. 12-15 , the vehicleaccessories 290 include a first accessory, shown as alternator 292, asecond accessory, shown as air conditioning compressor 294, and a thirdaccessory, shown as chassis air compressor 296. Each of the vehicleaccessories 290 is coupled to a respective one of the accessory pulleys276. In other embodiments, more, fewer, and/or different accessories areincluded within the accessory drive 270.

According to an exemplary embodiment shown in FIGS. 10 and 12 , theaccessory drive 270 is arranged in a through-shaftconfiguration/arrangement where the drive pulley 280 of the accessorypulley assembly 274 is coupled to the ETD interface 226 such that theETD shaft 230 and the ETD interface 226 extend through the drive pulley280 (i.e., the drive pulley 280 is positioned around the ETD interface226 such that the ETD shaft 230 appears to extends through the drivepulley 280). The accessory drive 270 may be driven by the engine 210 orthe ETD 240. By way of example, the engine 210 may drive the accessorydrive 270 to facilitate operating the vehicle accessories 290 when theETD clutch 234 is engaged. By way of another example, the ETD 240 maydrive the accessory drive 270 to facilitate operating the vehicleaccessories 290 when the ETD clutch 234 is disengaged (e.g., the ETD 240may drive the ETD interface 226 using power stored in the battery pack260, etc.). In an alternative embodiment, the accessory drive 270 isdriven by an independent motor and/or one or more of the accessoriesthemselves are electrically operated/driven.

According to an exemplary embodiment, the hybrid powertrain 200 of thefire fighting vehicle 10 is configured to provide improved performancerelative to a traditional, internal combustion engine driven powertrain.Specifically, commercially available ARFF vehicles include internalcombustion engine driven powertrains. Such powertrains include largeinternal combustion engines that are not very eco-friendly and providean acceleration from 0 to 50 miles-per-hour (“mph”) or 80kilometers-per-hour (“kph”) in greater than 30 seconds (e.g., 31seconds, 33 seconds, etc.). On the other hand, the hybrid powertrain 200of the present disclosure provides a more eco-friendly powertrain thatcan provide an acceleration from 0 to 50 mph in less than 30 secondswhile using a much smaller internal combustion engine. According to anexemplary embodiment, the fire fighting vehicle 10 (i) includes anengine that is less than 750 hp (e.g., between 500 hp and 600 hp,approximately 550 hp, approximately 650 hp, approximately 700 hp,between 600 hp and 750 hp, less than 650 hp, less than 600 hp, less than550 hp, etc.), (ii) includes battery pack with a battery capacity lessthan 60 kWh (e.g., 28 kWh, between 20 kWh and 40 kWh, between 12 kWh and60 kWh, etc.), (iii) has a water capacity of at least 1,000 gallons(e.g., between 1,000 and 4,500 gallons; at least 1,250 gallons; between2,500 gallons and 3,500 gallons; at most 4,500 gallons; at most 3,000gallons; at most 1,500 gallons; etc.), and (iv) has an agent capacity ofat least 150 gallons (e.g., between 150 gallons and 540 gallons, at most540 gallons, at most 420 gallons, at most 210 gallons, between 350gallons and 450 gallons, between 150 gallons and 250 gallons, etc.), allwhile accelerating from 0 to 50 mph in 30 seconds or less (e.g., 28seconds or less, 25 seconds or less, 22 seconds or less, etc.) with thewater and/or agent tanks full. However, it should be understood that, inother embodiments, the specifications of the engine 210, the batterypack 260, the water tank 110, and the agent tank 120 can be any of thespecifications disclosed herein.

Control System

According to the exemplary embodiment shown in FIG. 16 , a controlsystem 500 for the fire fighting vehicle 10 includes a controller 510.In one embodiment, the controller 510 is configured to selectivelyengage, selectively disengage, control, or otherwise communicate withcomponents of the fire fighting vehicle 10. As shown in FIG. 16 , thecontroller 510 is coupled to (e.g., communicably coupled to) componentsof the fluid delivery system 100 (e.g., the pump system 140, the turret180, etc.), components of the hybrid powertrain 200 (e.g., the engine210, the power divider 220, the engine clutch 235, electric motor 236,the ETD 240, the PTO 241, etc.), a user input/output device, shown asuser interface 520, various sensors, shown as sensors 530, a brake,shown as parking brake 550, and a battery management system (“BMS”),shown as BMS 560. By way of example, the controller 510 may send andreceive signals (e.g., control signals) with the components of the fluiddelivery system 100, the components of the hybrid powertrain 200, theuser interface 520, the sensors 530, the parking brake 550, and/or theBMS 560. As example, the controller 510 may receive data from the BMS560 regarding the battery pack 260 (e.g., battery pack voltage, etc.) oruser inputs from the user interface 520 (e.g., activate pump system 140,open structural discharge 170, etc.), and may send command signals tothe engine 210, the power divider 220, and/or the ETD 240 (e.g., engageETD clutch 234, back-start the engine 210, etc.). As another example,the controller 510 may be configured to selectively control the speed ofthe engine 210 (e.g., interface with a throttle thereof, etc.) such thatan output of engine 210 rotates at a target speed based on the mode ofoperation the hybrid powertrain 200 (e.g., a rollout mode, a standbymode, a normal mode, an accessory mode, etc.). As still another example,the controller 510 may provide a seamless operator experience. Forexample, the controller 510 may automatically engage various mode ofoperation (e.g., a rollout mode, standby mode, etc.) or engage variousmodes in response to receiving a corresponding user input/command (e.g.,from the user interface 520). This seamless experience may ensure thatthe operator does not have to manually control one or more components(e.g., the pumps, etc.).

The controller 510 may be implemented as a general-purpose processor, anapplication specific integrated circuit (“ASIC”), one or more fieldprogrammable gate arrays (“FPGAs”), a digital-signal-processor (“DSP”),circuits containing one or more processing components, circuitry forsupporting a microprocessor, a group of processing components, or othersuitable electronic processing components. According to the exemplaryembodiment shown in FIG. 16 , the controller 510 includes a processingcircuit 512 and a memory 514. The processing circuit 512 may include anASIC, one or more FPGAs, a DSP, circuits containing one or moreprocessing components, circuitry for supporting a microprocessor, agroup of processing components, or other suitable electronic processingcomponents. In some embodiments, the processing circuit 512 isconfigured to execute computer code stored in the memory 514 tofacilitate the activities described herein. The memory 514 may be anyvolatile or non-volatile computer-readable storage medium capable ofstoring data or computer code relating to the activities describedherein. According to an exemplary embodiment, the memory 514 includescomputer code modules (e.g., executable code, object code, source code,script code, machine code, etc.) configured for execution by theprocessing circuit 512. The memory 514 includes various actuationprofiles corresponding to modes of operation (e.g., for the fluiddelivery system 100, for the fire fighting vehicle 10, etc.), accordingto an exemplary embodiment. In some embodiments, the controller 510 mayrepresent a collection of processing devices (e.g., servers, datacenters, etc.). In such cases, the processing circuit 512 represents thecollective processors of the devices, and the memory 514 represents thecollective storage devices of the devices.

The user interface 520 includes a display and an operator input,according to one embodiment. The display may be configured to display agraphical user interface, an image, an icon, or still other information.In one embodiment, the display includes a graphical user interfaceconfigured to provide general information about the vehicle (e.g.,vehicle speed, fuel level, warning lights, agent levels, water levels,etc.). The graphical user interface may also be configured to display acurrent mode of operation, various potential modes of operation, orstill other information relating to the fire fighting vehicle 10, thefluid delivery system 100, and/or the hybrid powertrain 200. By way ofexample, the graphical user interface may be configured to providespecific information regarding the operation of fluid delivery system100 (e.g., whether the pump clutch 70, the turret 180, the hose reel 190are engaged or disengaged; whether a first mode of operation or a secondmode of operation is engaged; pressure and flow data; etc.).

The operator input may be used by an operator to provide commands to thecomponents of the fluid delivery system 100, the components of thehybrid powertrain 200, the parking brake 550, and/or still othercomponents or systems of the fire fighting vehicle 10. The operatorinput may include one or more buttons, knobs, touchscreens, switches,levers, joysticks, pedals, or handles. In one embodiment, an operatormay press a button and/or otherwise interface with the operator input tochange a mode of operation for the fluid delivery system 100 and/or thehybrid powertrain 200. The operator may be able to manually control someor all aspects of the operation of the fluid delivery system 100, thehybrid powertrain 200, and/or other components of the fire fightingvehicle 10 using the display and the operator input. It should beunderstood that any type of display or input controls may be implementedwith the systems and methods described herein.

In some embodiments, controller 510 is configured to generate controlsignals for the hybrid powertrain 200 to operate the hybrid powertrain200. For example, the controller 510 may monitor a required horsepower(e.g., a required input power) of the pump system 140, hp_(req) for aparticular application. If the required horsepower, hp_(req), is lessthan a threshold value, hp_(threshold) (i.e., hp_(req)<hp_(threshold))or less than or equal to the threshold value (i.e., hp_(req)hp_(threshold)), the controller 510 may generate control signals for thehybrid powertrain 200 so that the ETD 240 drives the pump system 140(e.g., through the power divider 220 and/or through the PTO 241). If therequired horsepower hp_(req) is greater than the threshold valuehp_(threshold) (i.e., hp_(req)>hp_(threshold)) or greater than or equalto the threshold value (i.e., hp_(req)≥hp_(threshold)), the controller510 may drive the pump system 140 with the engine 210 and/or theelectric motor 236 (e.g., if an electric motor is used in place of theengine 210).

As shown in FIG. 16 , the sensors 530 include a global positioningsystem (“GPS”) 532, an incline sensor 534, one or more battery sensors536, a speed sensor 538, and one or more clutch sensors 540. In someembodiments, the fire fighting vehicle 10 includes additional ordifferent sensors configured to measure or monitor various operationalparameters of the hybrid powertrain 200, the fluid delivery system 100,and/or the fire fighting vehicle 10. For example, the sensors 530 mayinclude speed sensors that are configured to measure an angular speed ofthe engine 210, the pump clutch 232, the ETD clutch 234, and/or variouscomponents of the ETD 240, etc. The sensors 530 may be integrated intovarious systems, subsystems, etc. of the fire fighting vehicle 10. Forexample, the sensors 530 can be integrated into or communicably coupledwith an engine control unit (“ECU”) of the fire fighting vehicle 10.

The GPS 532 may be configured to measure and provide the controller 510with an approximate global location of the fire fighting vehicle 10. Forexample, the GPS 532 may be configured to measure a latitude andlongitude of the fire fighting vehicle 10 and provide the controller 510with the measured latitude and longitude. The controller 510 may receivethe latitude and longitude from the GPS 532 and determine a rate ofchange of the latitude and/or the longitude to determine a speed of thefire fighting vehicle 10. The controller 510 may be configured todetermine a rate of change of the speed of the fire fighting vehicle 10to determine an acceleration of the fire fighting vehicle 10.

The incline sensor 534 may be any sensor configured to provide anincline of the fire fighting vehicle 10 (e.g., an indication of thegrade upon which the fire fighting vehicle 10 is currently traveling, anangle of the fire fighting vehicle 10 relative to the direction ofgravity, etc.). By way of example, the incline sensor 534 may be orinclude an inclinometer or a gyroscopic sensor. Alternatively, the GPS532 may include the incline sensor 534. By way of example, sensor datafrom the GPS 532 indicating the current global location of the firefighting vehicle 10 may be correlated to the incline at various globallocations. The controller 510 or the GPS 532 may store data correlatingglobal locations to associated inclines at those locations. Based on thecurrent global location, the current speed and direction of travel(e.g., provided by the speed sensor 326 and/or the GPS 532), and thedata correlating global locations to corresponding inclines, thecontroller 510 may be configured to determine a current incline and/orpredict a future incline of the fire fighting vehicle 10 based on sensordata

The battery sensors 536 may be or include one or more sensors coupled tothe battery pack 260 and the BMS 560. In some embodiments, the batterysensors 536 may include temperature sensors, voltage sensors, currentsensors, and other sensors that may be utilized to determinetemperature, state-of-health (“SoH”), state-of-charge (“SoC”), and/orother metrics that affect the health and performance of the battery pack260. For example, the battery sensors 536 may provide real-timemeasurements of voltage and/or current sourced or discharged by one ormore cells of the battery pack 260, and real-time measurements ofindividual cell temperatures for each cell of the battery pack 260.

The speed sensor 538 may be any sensor that is configured to measure avelocity of the fire fighting vehicle 10. For example, the speed sensor538 may be positioned at the front wheels 14 and/or the rear wheels 16of the fire fighting vehicle 10. The clutch sensors 540 may beconfigured to (i) monitor a status (e.g., engaged, dis-engaged, etc.) ofthe pump clutch 232 and/or the ETD clutch 234 and (ii) provide thestatus of the pump clutch 232 and/or the ETD clutch 234 to thecontroller 510. It should be understood that the controller 510 can becommunicably coupled with the ECU and/or a transmission control unit(“TCU”) of the fire fighting vehicle 10 and may receive any of theinformation or data of any of the systems, subsystems, control units,etc. of the fire fighting vehicle 10.

The BMS 560 may control charging and discharging of the battery pack 260by monitoring metrics such as battery temperature, SoH, SoC, etc. tomaximize the health and longevity of the battery pack 260 and maintainadequate charge within the battery pack 260. Additionally, the BMS 560may act to balance the charging and discharging of each of the cells ofthe battery pack 260. The BMS 560 generally operates by receiving andanalyzing sensor data from the battery sensors 536 and sending controldata to the controller 510 based on the analyzed data. For example, theBMS 560 may analyze data from the battery sensors 536 to determine thecurrent SoC of the battery pack 260. If the SoC of the battery pack 260is below a predetermined threshold, as described below with respect toFIG. 17 , the BMS 560 may send data to the controller 510, indicatingthat the battery pack 260 needs to be charged. As mentioned above, SoCis generally a measure of the charge level of a battery, often expressedas a percentage of maximum charge. SoH is generally a measure of theremaining capacity of a battery, often expressed as a percentage of theoriginal capacity of a battery.

In some embodiments, the BMS 560 may incorporate measurements or knownvalues of internal resistance, capacity, age, number of charge-dischargecycles, etc. of the battery pack 260, in addition to temperature,voltage, and current measurements, and apply the data to one or moreanalytical methods such as current integration, Kalman filtering, knowndischarge curves, etc. to determine SoH and SoC of the battery pack 260.In some embodiments, the BMS 560 may monitor charge cycling (i.e.,charge-discharge cycles) to determine the SoH of the battery pack 260and to allow the controller 510 to limit the quantity of charge cyclesand depth-of-discharge (“DoD”) or SoC for each cycle, as furtherdiscussed below.

In some embodiments, the BMS 560 may account for battery degradationwhen analyzing sensor data. For example, the BMS 560 may incorporate anyof the data discussed above (e.g., internal resistance, age, number ofcharge cycles, etc.) when determining the SoH or SoC of the battery pack260. It is known that battery degradation affects the SoH and SoC of abattery by reducing the SoH of the battery and by limiting the maximumSoC of a battery. For example, a battery that has experienced only 10charge cycles may reach 99% SoC with respect to a new battery, while abattery that has experienced 1,000 charge cycles may only reach 92% SoCwith respect to a new battery. In some embodiments, the controller 510may adapt control decisions in response to battery degradation, asdetermined by the BMS 560 and further discussed below.

Energy Management

As a general overview, the controller 510 may be configured to manageSoC, SoH, and temperature of the battery pack 260. As an example, thecontroller 510 may be configured to (i) prevent charging the batterypack above a maximum SoC threshold (e.g., maintain SoC at less than100%), (ii) limit DoD during discharge events (e.g., above 50% whenpossible), and (iii) limit battery temperature to prevent degradation ofthe SoH of the battery pack. As another example, the controller 510 maybe configured to control the engine 210, the ETD 240, and the batterypack 260 to consistently provide a SoC of the battery pack 260 thatfacilitates operating the fire fighting vehicle 10 at maximumacceleration (e.g., 0-50 mph in under 30 seconds) and top speed for adesignated period of time (e.g., three minutes). As still anotherexample, the controller 510 may be configured to adapt the controlscheme as the SoH of the battery pack degrades. For example, thecontroller 510 may be configured to reduce the maximum SoC threshold asthe battery pack 260 degrades or allow for increased DoD so that the SoCcan be further depleted during operation as the battery pack 260degrades.

Referring now to FIG. 17 , a graph 600 presenting example temperature,SoH, and SoC values is shown, according to some embodiments. Asdiscussed above, temperature, SoH, and SoC are metrics that the BMS 560may calculate and/or analyze based on data from the battery sensors 536to monitor the health and maintain the performance of the battery pack260. Graph 600 is shown to include three operating zones, zone 610(“LOW”), zone 620 (“MID”), and zone 630 (“HIGH”). Graph 600 is alsoshown to include three variables, X, Y, and Z, which may generally bedefined as threshold values. Zone 610 is shown to include values between0% and X %, where X % may be a value that defines an upper limit of zone610 (e.g., 50%). Zone 620 is shown to include values between X % and Y%, where X % may be a value that defines a lower limit of zone 620 and Y% may be a value that defines an upper limit of zone 620 (e.g., 50% to80%). Similarly, zone 630 is shown to include values between Y % and Z%, where Y % may be a value that defines a lower limit of zone 630 and Z% may be a value that defines an upper limit of zone 630 (e.g., 80% to90%). In some embodiments, Z may be equal to 100% (e.g., 100% SoC, 100%SoH), although it may be beneficial to set Z to a lower value (e.g., 90%SoC) for at least the reasons described below.

In some embodiments, the initial values of X, Y, and Z may be set by amanufacturer of the battery pack 260 based on the battery pack 260construction, attributes, and/or test data. In some embodiments, theinitial values of X, Y, and Z may be set by a manufacturer of the firefighting vehicle 10 based on similar or other data. In some embodiments,the threshold values (e.g., X, Y, and Z) may be dynamic, such thatcontroller 510 may determine threshold values based on the SoH or otherproperties of the battery pack 260. For example, as the SoH of thebattery pack 260 decreases (i.e., as the batteries degrade) over time,the controller 510 may adjust the SoC threshold values, represented byX, Y, and Z with regards to FIG. 17 , to ensure that the performance ofthe fire fighting vehicle 10 is preserved as the battery pack 260 ages.More generally, as the battery pack 260 ages, the controller 510 mayraise or lower the threshold values for at least one of X, Y, or Z tocompensate. In some embodiments, the threshold values of X, Y, and Z maybe adjusted by the controller 510 for other reasons. For example, thecontroller 510 may raise or lower the value of X, Y, and Z based onoperating conditions (e.g., severe service conditions, high externaltemperatures, etc.) or based on the charge and discharge rates of thebattery pack 260.

For at least those reasons described above, and further described below,the ability of the controller 510 to adjust threshold values based atleast on the SoH of the battery pack 260, operating conditions, and/orcharge/discharge rates may be advantageous in ensuring that the firefighting vehicle 10 maintains operational readiness at all times. Byadjusting threshold values, the controller 510 can ensure that thebattery pack 260, even with age, can provide adequate energy for normaland emergency operations. This allows the fire fighting vehicle 10 tomaintain response capabilities (e.g., response times, 0-50 mph times,operational modes, etc.) for the lifetime of the fire fighting vehicle10. Additionally, this may reduce the need for replacement of thebattery pack 260 due to age within the lifetime of the fire fightingvehicle 10.

As shown in FIG. 17 , graph 600 includes an example temperature(“Temp.”) value, shown within zone 610. The temperature value mayrepresent the temperature as a percentage of a maximum operatingtemperature of the battery pack 260. For example, the temperature valuemay represent a battery temperature of 20% indicating that the batterypack 260 is at 20% of its maximum operating temperature. In someembodiments, it may be beneficial to maintain battery temperatureswithin zone 610, with respect to graph 600, as higher batterytemperatures may lead to battery degradation, reducing the effectivelifetime (i.e., reducing the SoH) of the battery pack 260. In someembodiments, it may also be beneficial to maintain battery temperaturesabove a threshold, such as in zone 620, to avoid decreased batteryperformance due to cold temperatures.

As shown in FIG. 17 , graph 600 includes an example SoH value, shownwithin zone 630. The SoH value may represent the SoH of the battery pack260. In some embodiments, it may be beneficial to monitor the SoH of thebattery pack 260, as the battery pack 260 may become ineffective below athreshold value. For example, a healthy battery pack may have a SoHvalue within zone 630, while an old (i.e., approaching end-of-life(“EoL”)), worn, or otherwise defective battery pack may have a SoH valuewithin zone 620 or zone 610. In some instances, it may be beneficial toreplace an old, worn, or otherwise defective battery pack to maintainoperational readiness of the fire fighting vehicle 10.

Also shown in FIG. 17 , graph 600 includes an example SoC value, shownwithin zone 630. The SoC value may represent the SoC of the battery pack260. In some embodiments, it may be beneficial to monitor the SoC of thebattery pack 260 to ensure that the battery pack 260 maintains adequatecharge for normal or emergency operations of the fire fighting vehicle10. For example, if the SoC of the battery pack 260 falls below acertain threshold (e.g., the SoC is within zone 610), the battery pack260 may not have enough charge to meet the performance demands of thefire fighting vehicle 10 (e.g., providing energy to the ETD 240 to drivethe front axle 252 and/or the rear axle 254, back-start the engine 210,drive the accessory drive 270, etc.). Additionally, monitoring the SoCof the battery pack 260 may allow the controller 510 to prevent chargecycling from fully charged to fully depleted, or to prevent the batteryfrom being charged to 100% capacity, as both increased charge cyclingand high SoC (e.g., at or near 100%) may increase battery degradation.

It may be desirable to maintain a SoC within the battery pack 260 suchthat the SoC of the battery pack 260 falls within zone 630, with respectto FIG. 17 . As described above, zone 630 may include a lower limit andan upper limit, represented by Y % and Z % on graph 600. In someembodiments, Y % may be the lower limit of the desired SoC for thebattery pack 260 (e.g., 80%). For example, the BMS 560 may facilitatecharging of the battery pack 260 if the SoC of the battery pack 260falls below or approaches Y %. In some embodiments, Z % may be the upperlimit of the desired SoC for the battery pack 260 (e.g., 90%). While theupper limit of the SoC may be 100%, in some embodiments it may bedesirable for the upper limit of the SoC to be lower. By preventing theSoC of the battery pack 260 from exceeding a threshold value that isbelow 100% SoC, the risk of overcharging the battery pack 260 isreduced. Additionally, charging the battery pack 260 to an upperthreshold below 100% may increase battery life (i.e., maintain SoH), ascharge cycling to and from 100% SoC is shown to significantly reduce theeffective lifetime of a battery.

As described above and with respect to FIGS. 16 and 17 , the controller510 is configured to selectively engage, selectively disengage, control,or otherwise communicate with the engine 210, the power divider 220, theETD 240, the user interface 520, and the BMS 560. According to anexemplary embodiment, the controller 510 may communicate with the BMS560 by receiving data related to charging and discharging the batterypack 260. For example, the controller 510 may receive data from the BMS560 indicating that the battery pack 260 is below a threshold voltage orSoC, as described above. The controller 510 may then control the powerdivider 220 and the ETD 240 to charge the battery pack 260, such as byengaging the ETD clutch 234 to provide engine power to the ETD 240, andengaging one or more brakes and/or clutches within the ETD 240 to causeat least one of the electromagnetic devices of the ETD 240 to generateelectricity.

As further described below, by monitoring battery charge levels andcontrolling charge cycling, the controller 510 and the BMS 560 mayensure that the battery pack 260 maintains an adequate amount of chargeto allow for full response of the fire fighting vehicle 10 at anymoment. Additionally, it is known that charge cycling, deep dischargeevents, and/or charging a battery to near 100% capacity can lead toincreased battery degradation, as discussed above. Monitoring andcontrolling the quantity of charge cycles, as well as the DoD and SoC ofthe battery pack 260, may reduce battery degradation, thereby extendingthe effective lifetime of the battery pack 260.

In some embodiments, the controller 510 is configured to determine thatthe temperature of the battery pack 260 is outside of a desiredoperating range (e.g., outside of zone 610). For example, the controller510 may determine that the temperature of the battery pack 260 iscurrently 75% of the maximum operating temperature, based on data fromthe BMS 560, which falls outside of the desired operating range. In suchembodiments, the controller 510 may limit battery charge cycling in aneffort to reduce the temperature of the battery pack 260. For example,the controller 510 may limit the ETD 240 to operating modes that do notcharge the battery pack 260, as charging increases battery temperature.In another example, the controller 510 may limit the ETD 240 tooperating modes that do not draw energy from the battery pack 260, or tooperating modes that limit the amount of energy sourced from the batterypack 260. In some embodiments, the battery pack 260 or the BMS 560 mayinclude fans that are operable to cool the battery pack 260. Thecontroller 510 may activate such fans in an effort to further reducebattery temperatures and maintain operational readiness.

In some embodiments, the controller 510 is configured to determine thatthe SoC of the battery pack 260 is within an ideal range (e.g., “HIGH,”zone 630, above threshold value Y). For example, the controller 510 maydetermine that the SoC of the battery pack 260 is currently 88% based ondata from the BMS 560, which falls into a predetermined “ideal” or“high” range (e.g., from 80%-90%). When the SoC of the battery pack 260is within an ideal range, the controller 510 may determine that thebattery pack 260 is capable of providing adequate energy and performancein a plurality of operating modes. The controller 510 may then controlor communicate with the engine 210, the power divider 220, and/or theETD 240 to maximize performance of the fire fighting vehicle 10. Forexample, a sufficiently charged battery such as the battery pack 260 mayallow the ETD 240 to operate such that one or both of theelectromagnetic devices utilize energy from the battery pack 260 toperform operations such as back-starting the engine 210, driving theaccessory drive 270, driving the front axle 252 and/or the rear axle(s)254, etc. as described in greater detail herein. In another example, thecontroller 510 may communicate with or control the power divider 220 toengage the ETD clutch 234 so that the ETD 240 operate in unison with theengine 210 to provide hybrid power for driving the fire fighting vehicle10.

In some embodiments, the controller 510 may determine that the SoC ofthe battery pack 260 is within an adequate operating range (e.g., “MID”,zone 620, between threshold values X and Y). For example, the controller510 may determine that the SoC of the battery pack 260 is currently 65%based on data from the BMS 560, which falls into a predeterminedoperating range (e.g., from 50%-80%). When the SoC of the battery pack260 is within such a range, the controller 510 may determine that thebattery pack 260 is capable of providing adequate energy and performancein a plurality of operating modes, however, the controller 510 mayprioritize operations within modes that charge the battery pack 260. Thecontroller 510 may then control or communicate with the engine 210, thepower divider 220, and/or the ETD 240 to allow increased performance ofthe fire fighting vehicle 10 while providing energy to the battery pack260. For example, a partially discharged battery, such as battery pack260, may allow the ETD 240 to operate in any of the modes describedabove for a limited amount of time. The controller 510 may prioritizecharging of the battery pack 260 by controlling the ETD 240 to operatein modes such that one or both of the electromagnetic devices of the ETD240 are driven by the engine 210 to generate electricity.

In some embodiments, additional energy is required from the battery pack260 when in a less than ideal SoC range, or charging the battery pack260 is not feasible, such as when responding to an emergency situation.For example, when responding to an emergency, the fire fighting vehicle10 may require immediate acceleration provided by the hybrid powertrain200. In such embodiments, the controller 510 may limit the charging ofthe battery pack 260 to increase performance of the fire fightingvehicle 10. In some embodiments, the controller 510 may allow thebattery pack 260 to reach a lower threshold of the operating zone (e.g.,50%, threshold value X) in severe or emergency operations, beforerequiring charging of the battery pack 260. In this regard, thecontroller 510 may prioritize performance over charging of the batterypack 260 in order to provide the range and operating speeds required forthe fire fighting vehicle 10. As described above, the controller 510 mayalso adjust one or more threshold values based on age of the batterypack 260, operating conditions, charge/discharge rates, etc. to maintainperformance of the fire fighting vehicle 10.

In some embodiments, the controller 510 is configured to determine thatthe SoC of the battery pack 260 is outside of an adequate operatingrange (e.g., “LOW”, zone 610, below threshold value X). For example, thecontroller 510 may determine that the SoC of the battery pack 260 iscurrently 45% based on data from the BMS 560, which falls outside of anoperating range (e.g., below a 50% lower limit of an operating zone).When the SoC of the battery pack 260 is within a low range, or outsidethe operating range, the controller 510 may determine that the batterypack 260 is no longer capable of providing adequate energy andperformance. The controller 510 may then control or communicate with theengine 210, the power divider 220, and/or the ETD 240 to limit operatingmodes to modes that provide energy to the battery pack 260. For example,a discharged battery, such as the battery pack 260, may not provideenough energy to achieve immediate acceleration of the fire fightingvehicle 10, or may not provide adequate range. The controller 510 maythen charge the battery pack 260 by controlling the ETD 240 to operatein modes such that one or both of the electromagnetic devices of the ETD240 are driven by the engine 210 to generate electricity.

Operational Modes

As a general overview, the controller 510 is configured to operate thehybrid powertrain 200 in various operational modes. In some embodiments,the controller 510 generates the control signals for the variouscomponents of the hybrid powertrain 200 to transition the hybridpowertrain 200 between the various operational modes in response toreceiving a user input, a command, a request, etc. from the userinterface 520. In some embodiments, the controller 510 is configured toadditionally or alternatively analyze sensor data received from one ormore of the sensors 530 and transition the hybrid powertrain 200 betweenthe various operational modes based on the sensor data. The variousoperational modes of the hybrid powertrain 200 may include a hybridmode, a standby/accessory-drive mode, a rollout/all-electric-drive mode,an ultra-low mode, a pump-and-roll mode, and/or still other modes.

Standby Mode

The controller 510 may be configured to transition the fire fightingvehicle 10 into a standby mode of operation. The standby mode mayinclude de-coupling the engine 210 from the accessory drive 270 so thatthe engine 210 can be shutdown. The accessory drive 270 can be run usingenergy received from the battery pack 260, without requiring an inputfrom the engine 210 (e.g., mechanical energy input, drive input, etc.).The accessory drive 270 may be driven so that the various vehicleaccessories 290 can be driven (e.g., an HVAC system of the fire fightingvehicle 10, warning lights, radios, etc.) without requiring operation ofthe engine 210. Advantageously, this can improve the efficiency of thefire fighting vehicle 10, while reducing emissions that may be producedby operation of the engine 210.

The controller 510 may transition the hybrid powertrain 200 into thestandby mode in response to receiving a user or operator input from theuser interface 520. In some embodiments, the controller 510 transitionsthe hybrid powertrain 200 into the standby mode automatically. Forexample, if the controller 510 determines, based on the sensor data,that the fire fighting vehicle 10 has been stationary for apredetermined amount of time, the controller 510 may automaticallytransition the hybrid powertrain 200 into the standby mode. In someembodiments, the controller 510 is selectively actuatable between theautomatic and the manual mode. For example, the controller 510 canreceive a user input from the user interface 520 that the hybridpowertrain 200 should be automatically transitioned between other modesof operation and the standby mode. When the controller 510 is in theautomatic mode, the controller 510 automatically transitions the hybridpowertrain 200 into the standby mode without requiring user inputs(e.g., in response to the fire fighting vehicle 10 being stationary forsome amount of time). When the controller 510 is in the manual mode, thecontroller 510 only transitions the hybrid powertrain 200 into thestandby mode in response to receiving a user input from the userinterface 520.

When transitioning the fire fighting vehicle 10 and/or the hybridpowertrain 200 into the standby mode, the controller 510 may firstoperate a parking brake 550 of the fire fighting vehicle 10 totransition the parking brake 550 into an engaged state. In someembodiments, the parking brake 550 is operated manually by a user andthe controller 510 receives a brake status from parking brake 550. Insome embodiments, the controller 510 operates a display device (e.g., alight, a speaker, a display screen, etc.) to prompt the user to set theparking brake 550. The controller 510 may monitor the brake status ofthe parking brake 550 to ensure that the parking brake 550 is set (e.g.,transitioned into the engaged state) before proceeding. The parkingbrake 550 can be selectively actuated between the engaged state and adisengaged state. The controller 510 may then check the SOC of thebattery pack 260. In some embodiments, the controller 510 onlytransitions into the standby mode in response to a sufficient amount ofelectrical energy remaining in or being present in the battery pack 260.The controller 510 can perform a process to determine the SOC of thebattery pack 260.

In response to the SOC of the battery pack 260 being sufficient totransition into the standby mode, the controller 510 may generatecontrol signals for the engine 210 to transition the engine 210 into anoff-state or a standby state. In some embodiments, the controller 510transitions the engine 210 completely into the off-state or the standbystate so that the engine 210 is not running. The controller 510 cangenerate shut-off or shut-down control signals for the engine 210 andprovide the shut-off control signals to the engine 210.

The controller 510 may also generate control signals for the ETD clutch234 of the power divider 220 to de-couple the engine 210 from theaccessory drive 270. The controller 510 may then generate controlsignals for the ETD 240 to draw power from the battery pack 260 tooperate or drive the accessory drive 270. In this way, the controller510 can de-couple and shut down the engine 210 from the accessory drive270 so that the ETD 240 drives the accessory drive 270 without requiringinput from the engine 210. Advantageously, this reduces fuelconsumption, improves efficiency, and reduces emissions of the firefighting vehicle 10.

In the standby mode, the controller 510 may also generate controlsignals for the pump clutch 232 to couple or de-couple the pump system140 from the engine 210. In some embodiments, the pump system 140 may beable to be driven by the ETD 240.

The controller 510 may transition the hybrid powertrain 200 and/or thefire fighting vehicle 10 into the standby mode at an end of a runway ora desired destination. For example, when the fire fighting vehicle 10reaches the end of the runway or the desired destination, and the engine210 is not required (e.g., to drive the pump system 140), the controller510 can automatically or manually transition into the hybrid powertrain200 and/or the fire fighting vehicle 10 into the standby mode toconserve fuel consumption. Advantageously, the fire fighting vehicle 10can still drive the accessory drive 270 to thereby provide thefunctionality of the vehicle accessories 290.

Referring now to FIG. 19 , a method 700 for transitioning a firefighting vehicle (e.g., the fire fighting vehicle 10) and/or apowertrain (e.g., the hybrid powertrain 200) into a standby mode isshown, according to some embodiments. Method 700 include steps 702-712and can be performed by controller 510.

Method 700 includes receiving a user input to transition the firefighting vehicle and/or the powertrain into a standby mode (step 702),according to some embodiments. In some embodiments, step 702 includesreceiving the user input from a user interface (e.g., the user interface520) or from any other user interface, human machine interface, etc. ofthe fire fighting vehicle that is communicably coupled with controller510. Step 702 can initiate the transition into the standby mode. Inother embodiments, the transition into the standby mode is initiatedautomatically (e.g., in response to the controller 510 determining thatthe fire fighting vehicle has been stationary for a predetermined amountof time, at a certain location for a predetermined amount of time,etc.).

Method 700 includes setting a parking brake (e.g., the parking brake550) of the fire fighting vehicle 10 or monitoring the parking brake(step 704), according to some embodiments. The parking brake can beactivated so that the fire fighting vehicle does not roll or otherwisemove while in the standby mode. In some embodiments, the parking brakeis transitionable between an engaged state and a disengaged state. Theparking brake can be set (e.g., transitioned into the engaged state) bythe controller 510 or by a user. If the parking brake is set by theuser, the controller 510 may monitor a status of the parking brake andwait until the parking brake is set before proceeding to the next step.In some embodiments, step 704 is omitted.

Method 700 includes checking the SOC of a battery pack (e.g., thebattery pack 260) (step 706), according to some embodiments. Step 706can be performed by the controller 510 using a SOC process. Thecontroller 510 can check the SOC of the battery pack, a remaining amountof charge or electrical energy in the battery pack, a voltage of thebattery pack, a temperature of the battery pack, etc. The controller 510may use the SOC of the battery pack to determine if the battery pack cansufficiently provide electrical power for the standby mode.

Method 700 includes shutting off an engine (e.g., the engine 210) of thepowertrain (step 708), according to some embodiments. Step 708 can beperformed by the controller 510 by generating control signals to shutdown the engine and providing the control signals to the engine. Step708 may be performed by the controller 510 concurrently with step 710 asdescribed in greater detail below.

Method 700 includes opening a clutch (e.g., the ETD clutch 234) tode-couple the engine from an accessory drive (e.g., the accessory drive270) (step 710), according to some embodiments. In some embodiments,step 710 includes generating and providing control signals to the clutchto de-couple the engine from the accessory drive. Step 710 can beperformed by the controller 510 and may be performed prior to, orconcurrently with step 708.

Method 700 includes operating the accessory drive with anelectromechanical transmission (e.g., the ETD 240) for accessoryapplications (step 712), according to some embodiments. Step 712 can beperformed by the controller 510 and the electromechanical transmission.For example, the electromechanical transmission may draw power frombattery pack to drive the accessory drive, thereby driving vehicleaccessories (e.g., the vehicle accessories 290) coupled to the accessorydrive.

Rollout Mode

The controller 510 may be configured to transition the hybrid powertrain200 and/or the fire fighting vehicle 10 into a rollout mode. The rolloutmode may include several sub-modes between which the controller 510transitions the hybrid powertrain 200 and/or the fire fighting vehicle10 during operation. The rollout mode may improve the transport speed ofthe fire fighting vehicle 10 to a destination (e.g., the end of arunway, a plane crash site, a fire, etc.) and reduce emissions of thefire fighting vehicle 10.

When in the rollout mode, the controller 510 may generate controlsignals for the ETD clutch 234 to de-couple the engine 210 from the ETD240. The controller 510 may then generate control signals for the ETD240 and the battery pack 260 so that the ETD 240 draws electrical powerfrom the battery pack 260 to drive the front axle 252 and/or the rearaxle 254. The ETD 240 may, therefore, be used to drive the front axle252 and/or the rear axle 254 without requiring input from the engine210. In some embodiments, the controller 510 initially de-couples theengine 210 from the ETD 240 (by disengaging the ETD clutch 234) prior tostart-up or ignition of the engine 210. Once a predetermined conditionis met (e.g., after the fire fighting vehicle 10 has travelled apredetermined distance or is outside of a geofence, reached a certainspeed, reached a certain location, been driven for a period of time,etc.), the controller 510 may start the engine 210 and engage the ETDclutch 234 so that the engine 210 may provide an input to the ETD 240.In some embodiments, the engine 210 is started in response to thecontroller 510 receiving a command from the user interface 520. Theengine 210 may be started by the ETD 240 (e.g., by engaging the ETDclutch 234), or by a separate starter that is configured to start theengine 210. The controller 510 may generate control signals for (i) theETD 240 and/or the ETD clutch 234 and/or (ii) the separate starter tostart up the engine 210.

The controller 510 may, therefore, operate the ETD 240 and/or the ETDclutch 234 so that the fire fighting vehicle 10 can begin transportation(e.g., leaving a fire station, a hanger, etc.) to a desired location(e.g., the end of the runway, a plane crash site, a fire, etc.) withoutrequiring operation of the engine 210. Once the fire fighting vehicle 10has been transported or has travelled a certain distance or outside of ageofence, has reached a certain speed, is in a certain location (e.g., acertain location along the runway, a certain distance from the firestation/hanger, etc.), been driven for a period of time, the controller510 may start the engine 210 so that the engine 210 can be used toprovide a mechanical input to the ETD 240. The controller 510 may alsostart the engine 210 in response to receiving a user input from the userinterface 520. After the engine 210 has been started (or before, if theETD 240 is used to start the engine 210), the controller 510 can engagethe ETD clutch 234 so that the engine 210 can provide a mechanical inputto the ETD 240.

Advantageously, the rollout mode facilitates improved transportationspeed, particularly when the fire fighting vehicle 10 initially leaves alocation (e.g., a fire house, a hanger, etc.) to travel to a destination(e.g., the end of the runway, a plane crash site, a fire, etc.). Therollout mode may also facilitate preventing combustion emissions fromfilling the fire station or hanger upon startup and takeoff. Forexample, when in the rollout mode, the fire fighting vehicle 10 maybegin transportation to the destination without requiring startup of theengine 210. This can improve a response time (e.g., an amount of timefor the fire fighting vehicle 10 to leave its initial location andtravel to a destination) and combustion emission output for the firefighting vehicle 10. The engine 210 can then be started after the firefighting vehicle 10 has already begun transportation to the destination.

Referring to FIG. 20 , a method 800 for transitioning a fire fightingvehicle (e.g., the fire fighting vehicle 10) and/or a powertrain (e.g.,the hybrid powertrain 200) into a rollout mode is shown, according tosome embodiments. The rollout mode may include various sub-modes betweenwhich the powertrain and/or the fire fighting vehicle are transitionedduring the rollout mode. Method 800 can include steps 802-812 and may beperformed by the controller 510. The controller 510 may perform steps802-812 when the fire fighting vehicle initially leaves a storagelocation (e.g., a hanger, a fire station, etc.).

Method 800 includes disengaging an engine (e.g., the engine 210) from anelectromechanical transmission (e.g., the ETD 240) (step 802), accordingto some embodiments. Step 802 can be performed by the controller 510 andmay include providing control signals to a clutch (e.g., the ETD clutch234) to disengage or de-couple the electromechanical transmission fromthe engine. In some embodiments, step 802 is only performed if theelectromechanical transmission is currently engaged or coupled with theengine. The electromechanical transmission may be dis-engaged orde-coupled from the engine so that the electromechanical transmissioncan independently drive a front axle and/or a rear axle of the firefighting vehicle without requiring input from the engine.

Method 800 includes operating the electromechanical transmission usingenergy from a battery pack (e.g., the battery pack 260) totransport/propel the fire fighting vehicle (step 804), according to someembodiments. Step 804 can include drawing power from the battery packwith the electromechanical transmission and using the electrical powerto drive the front axle and/or the rear axle. Step 804 can be performedby controller 510, electromechanical transmission, and the battery pack.Advantageously, step 804 can be performed without requiring operation ofor mechanical input from the engine. Step 804 can be performed totransport the fire fighting vehicle when initially leaving a storagelocation, a hanger, a first location, etc.

Method 800 includes determining if the engine should be started (step806), according to some embodiments. Step 806 may be performed bycontroller 510 based on data received from sensors (e.g., the sensors530) and/or a user input received from a user interface (e.g., the userinterface 520). In some embodiments, the controller 510 determines thatthe engine should be started in response to determining a predeterminedcondition has been met (e.g., determining that the fire fighting vehiclehas achieved a predetermined speed, travelled a predetermined distanceor outside of a geofence, been driven by using only electricity from thebattery pack for a predetermined amount of time, reached a certainlocation, etc.). In other embodiments, controller 510 determines thatthe engine should be started in response to receiving a user input or anoperator command to start the engine.

In response to determining that the engine 210 should be started (step806, “YES”), method 800 proceeds to step 808. In response to determiningthat the engine 210 should not yet be started (step 806, “NO”), method800 returns to step 804 and continues transporting the fire fightingvehicle using the power drawn from the battery pack.

Method 800 includes starting the engine (step 808), according to someembodiments. Step 808 can be performed by the electromechanicaltransmission or with a separate starter designated for the engine. As anexample, the controller 510 may be configured to start the engine byengaging the clutch to couple the engine to the electromechanicaltransmission and back-starting the engine with the electromechanicaltransmission. As another example, the controller 510 may be configuredto start the engine by operating the separate starter. The separatestarter may receive electrical power from the battery pack or from otheron-vehicle electrical energy storage.

Method 800 includes engaging the engine with the electromechanicaltransmission (step 810), according to some embodiments. Step 810 can beperformed by the controller 510. The controller 510 may generate controlsignals for the clutch to couple the engine with the electromechanicaltransmission. Step 810 may be performed in response to step 808.Alternatively, step 810 may be performed prior to step 808 (e.g., step810 is performed in order to start the engine with the electromechanicaltransmission as described above).

Method 800 includes transporting the fire fighting vehicle using powerfrom the engine (step 812), according to some embodiments. Step 812 maybe performed in response to the engine being started (i.e., step 808)and in response to the engine being coupled or engaged with theelectromechanical transmission (i.e., step 810). Once the engine hasbeen started and engaged with the electromechanical transmission, theengine may be used to produce mechanical power to drive theelectromechanical transmission to produce electricity for (i) storage inthe battery pack and/or (ii) to drive the electromechanical transmissionin place of or in addition to the energy drawn from the battery pack.

Method 800 may be performed to reduce a required amount of time to startdriving the fire fighting vehicle 10. Instead, the fire fighting vehicle10 can use the ETD 240 and the battery pack 260 to initially begintransportation of the fire fighting vehicle 10. Once the fire fightingvehicle 10 has achieved the predetermined operating condition (e.g., arequired speed, travelled a predetermined distance or outside of ageofence, passed a certain location, etc.), the engine 210 may bestarted and the fire fighting vehicle 10 can use power from the engine210 to assist in transportation. Advantageously, this can reduce thetime required for the fire fighting vehicle 10 to arrive at adestination (e.g., the end of a runway, a crash site, a fire, etc.) andreduce emissions. Additionally, the ETD 240 may be configured to or becapable of providing mechanical power to front axle 252 and/or rear axle254 at higher torque (e.g., at low speeds) than the engine 210. Sincethe ETD 240 and the battery pack 260 are used in the rollout mode at lowspeeds, without using mechanical input from the engine 210, the higherlow speed torque may improve an acceleration of the fire fightingvehicle 10, thereby reducing the response time of the fire fightingvehicle 10.

Ultra-Low Mode

Referring to FIG. 18 , the controller 510 may be configured totransition hybrid powertrain 200 and/or the fire fighting vehicle 10into an ultra-low mode of operation (e.g., a high-torque mode, a slowspeed mode, a low speed mode, a high grade mode, etc.). The ultra-lowmode may be a sub-mode of the rollout mode, or the ultra-low mode may bea separate mode entirely. The ultra-low mode may be configured to drivethe fire fighting vehicle 10 at a low speed with a large amount ofavailable torque. The ultra-low mode may increase the gradability of thefire fighting vehicle 10 (e.g., facilitates the fire fighting vehicle 10maintaining speed while climbing large or steep grades and transportinglarge loads including the weight of the fire fighting vehicle 10, theweight of water and/or fire suppressing agent, etc.). In someembodiments, the ultra-low mode permits the fire fighting vehicle toclimb grades of up to or greater than a 50% grade (i.e., a 26.6 degreeincline).

When in the ultra-low mode, the controller 510 may generate controlsignals to disengage the ETD clutch 234 to de-couple the engine 210 fromthe ETD 240. The controller 510 may then generate control signals forthe ETD 240 to draw electrical power from the battery pack 260 to drivethe front axle 252 and/or the rear axle 254. Specifically, electricalpower from the battery pack 260 may be used to drive the firstmotor/generator 340 and/or the second motor/generator 350 to drive thefront axle 252 and/or the rear axle 254. The ETD 240, therefore, can beused to drive the front axle 252 and/or the rear axle 254 withoutrequiring input from the engine 210 and without providing a rotationalmechanical energy input to the engine 210. While in the ultra-low mode,the engine 210 may be turned off (e.g., to reduce emissions), or theengine 210 may be turned on (e.g., at idle, to drive one or morecomponents). By way of example, while in the ultra-low mode, the ETD 240may be used to drive the front axle 252 and/or the rear axle 254 whilethe engine 210 is used to drive the pump system 140 (e.g., through thepump clutch 232, a pump-and-roll mode of operation).

As shown in FIG. 18 , the transmission 330 of the ETD 240 is selectivelyreconfigured into the ultra-low mode such that rotation of the firstmotor/generator 340 and the second motor/generator 350 drives the outputshaft 332 to drive the front axle interface 244 and/or the rear axleinterface 246 (i.e., thereby driving the front axle 252 and/or the rearaxle 254). Both the first motor/generator 340 and the secondmotor/generator 350 may draw/consume electrical power from the batterypack 260 while in the ultra-low mode.

The power split coupled clutch 430, the input coupled clutch 440, andthe output coupled clutch 450 may be engaged by the controller 510 inthe ultra-low mode. As shown in FIG. 18 , the power split coupled clutch430 couples the gear set 480 to the output shaft 332, thereby couplingthe carrier 428 and the carrier 418 to the output shaft 332. The outputcoupled clutch 450 couples the gear set 490 to the output shaft 332,thereby coupling the ring gear 424 to the output shaft 332. The inputcoupled clutch 440 couples the second motor/generator 350 to theconnecting shaft 336, thereby coupling the sun gear 422 to the ring gear414. Accordingly, movement of the power split planetary 410 (i.e., thesun gear 412, the ring gear 414, the planetary gears 416, and thecarrier 418), the output planetary 420 (i.e., the sun gear 422, the ringgear 424, the planetary gears 426, and the carrier 428), the outputshaft 332, the connecting shaft 336, the first motor/generator 340, andthe second motor/generator 350 may be coupled (e.g., such that eachcomponent rotates relative to each other component at a fixed ratio).

According to the exemplary embodiment shown in FIG. 18 , an energy flowpath for the ultra-low mode includes: the first motor/generator 340providing a rotational mechanical energy input to the sun gear 412; thesun gear 412 causing the planetary gears 416 to rotate about the sungear 412 such that both the carrier 418 and the ring gear 414 rotate;and the carrier 418 driving the output shaft 332 through the gear set480 and the power split coupled clutch 430. Rotation of the ring gear414 may drive the second motor/generator 350 through the connectingshaft 336 and the input coupled clutch 440. Additionally, because thecarrier 418 and the carrier 428 are coupled to one another, rotation ofthe carrier 418 drives the planetary gears 426 to rotate about the sungear 422 and vice versa. Another energy flow path for the ultra-low modeincludes: the second motor/generator 350 providing a rotationalmechanical energy input to the sun gear 422; the sun gear 422 causingthe planetary gears 426 to rotate about the sun gear 422 such that boththe carrier 428 and the ring gear 424 rotate; and the ring gear 424driving the output shaft 332 through the gear set 490 and the outputcoupled clutch 450. Rotation of the output shaft 332 drives rotation ofthe rear axle 254 through the rear axle interface 246. The controller510 may engage the front declutch collar shift 334 to engage the frontaxle interface 244 such that rotation of the output shaft 332 drivesrotation of the front axle 252 through the front declutch collar shift334 and the front axle interface 244.

The controller 510 may transition the hybrid powertrain 200 into theultra-low mode in response to receiving a user or operator input fromthe user interface 520. In some embodiments, the controller 510transitions the hybrid powertrain 200 into the ultra-low modeautomatically. As an example, if the controller 510 determines, based onthe sensor data, that the fire fighting vehicle 10 has a high torquedemand, the controller 510 may automatically transition the hybridpowertrain 200 into the ultra-low mode. By way of example, thecontroller 510 may monitor a load on the engine 210 (e.g., by measuringan engine speed), the first motor/generator 340, and/or the secondmotor/generator 350 (e.g., by measuring a current draw) andautomatically transition the hybrid powertrain 200 into the ultra-lowmode in response to the load increasing above a threshold level. In suchan embodiment, the controller 510 may only transition the hybridpowertrain 200 into the ultra-low mode when the fire fighting vehicle 10is traveling at less than a threshold speed. As another example, if thecontroller 510 determines, based on the sensor data, that the firefighting vehicle 10 is traveling on a steep grade or is about to travelup a steep grade, the controller 510 may automatically transition thehybrid powertrain 200 into the ultra-low mode. By way of example, thecontroller 510 may use sensor data from the incline sensor 534 and/orthe GPS 532 to determine if the fire fighting vehicle 10 is traveling upa grade of greater than a threshold incline, and transition into theultra-low mode in response to such a determination. By way of anotherexample, the controller 510 may use sensor data from the incline sensor534 and/or the GPS 532 to determine if the fire fighting vehicle 10 willbe traveling up a grade of greater than a threshold incline in the nearfuture (e.g., within a threshold time period), and transition into theultra-low mode in response to such a determination.

The ultra-low mode may be utilized in other vehicle arrangements. By wayof example, the ultra-low mode may be utilized in any vehicle includingthe ETD 240 where the ETD 240 can be selectively coupled to an engine.By way of example, in such a vehicle, the power divider 220 may bereplaced with a single clutch (e.g., the ETD clutch 234, a clutch in agearbox, etc.) that selectively couples an engine (e.g., the engine 210)to the ETD 240. Such an arrangement may be used in a vehicle without apump clutch 232, the pump system 140, and/or the vehicle accessories290.

Hybrid Mode

The controller 510 may be configured to transition the hybrid powertrain200 and/or the fire fighting vehicle 10 into a hybrid mode and mayoperate the hybrid powertrain 200 and/or the fire fighting vehicle 10according to the hybrid mode. In some embodiments, the controller 510operates the hybrid powertrain 200 and/or the fire fighting vehicle 10in the hybrid mode whenever the engine 210 is operating (e.g., producingmechanical energy). When the controller 510 operates the hybridpowertrain 200 and/or the fire fighting vehicle 10 according to thehybrid mode, the ETD 240 is operated (e.g., by the controller 510) toreceive energy (e.g., mechanical, electrical, etc.) from the batterypack 260 and the engine 210 through the power divider 220. The ETD 240may operate to blend or combine the energy received from the engine 210and the battery pack 260 and operate to drive the front axle 252 and/orthe rear axle 254 continuously to optimize performance and efficiency.

Other Modes

The controller 510 may also be configured to transition the hybridpowertrain 200 and/or the fire fighting vehicle 10 between various othermodes of operation. For example, the controller 510 may transition thehybrid powertrain 200 and the fire fighting vehicle 10 into a pumpingmode of operation. The pumping mode of operation may include de-couplingor disengaging the ETD 240 from the engine 210, while engaging orcoupling the engine 210 to the pump system 140. In some embodiments, thecontroller 510 is configured to generate and provide control signals tothe pump clutch 232 and the ETD clutch 234. For example, the controller510 may generate control signals (i) for the ETD clutch 234 to disengagethe engine 210 from the ETD 240 and (ii) for the pump clutch 232 toengage the pump clutch 232, thereby coupling the pump system 140 withthe engine 210. In this way, the engine 210 can be used to drive thepump system 140 (e.g., to pump water and/or agent for fire suppression)without being used to drive the ETD 240. In some instances, the pumpclutch 232 and the ETD clutch 234 are both engaged such that amechanical input provided to the power divider 220 by the engine 210drives both the pump system 140 and the ETD 240 simultaneously.

In some embodiments, the controller 510 may also be configured totransition the hybrid powertrain 200 and/or the fire fighting vehicle 10into a drive mode. In some embodiments, the drive mode is the same as orsimilar to the rollout mode. The drive mode may include engaging the ETDclutch 234 while disengaging the pump clutch 232. For example, when thefire fighting vehicle 10 is transporting or travelling to a destination(e.g., the end of a runway), the pump system 140 may not be required tobe operated. In this way, all of the power produced by the engine 210can be used to drive the ETD 240 without operation of the pump system140.

The controller 510 may also selectively charge the battery pack 260using electricity generated by the ETD 240. In some embodiments, thecontroller 510 transitions the hybrid powertrain 200 and/or the firefighting vehicle 10 into a charging mode to charge the battery pack 260.For example, the controller 510 may generate control signals for theengine 210, the pump clutch 232, the ETD clutch 234, and the ETD 240 sothat the ETD 240 is driven by the engine 210 and used to charge thebattery pack 260. In some embodiments, during the charging mode, thecontroller 510 monitors or determines the SOC of the battery pack 260.

Alternative Configurations

Referring particularly to FIGS. 21-35 , alternative configurations ofthe hybrid powertrain 200 are shown, according to various embodiments.The hybrid powertrain 200 is capable of any of the configurationsdescribed herein or any combination of the various configurationsdescribed herein. FIGS. 21 and 22 show the hybrid powertrain 200configured for use with an electric motor, according to an exemplaryembodiment. FIG. 23 shows the hybrid powertrain 200 with another primarymover (e.g., a third primary mover) configured to drive the pump system140. FIG. 24 shows a configuration where the pump system 140 is drivenby the ETD 240, according to an exemplary embodiment. FIG. 25 shows aconfiguration of the hybrid powertrain 200 when the engine 210 is usedto drive a generator 238 that can provide electrical energy to any ofthe battery pack(s) 260, the ETD 240, a pump drive system (e.g., pumpmover 298), etc. FIG. 26 shows a configuration of the hybrid powertrain200 where the engine 210, the ETD 240, and the pump system 140 arearranged in-line with one another. FIG. 35 shows a configuration similarto the configuration of FIG. 26 , except the ETD 240 is replaced with anelectric drive module 1100.

Fully Electric Vehicle

Referring particularly to FIGS. 21 and 22 , the hybrid powertrain 200 ofthe fire fighting vehicle 10 is shown configured as a fully electricdrive system. In particular, the engine 210 is replaced with an electricmotor 236. The electric motor 236 can be configured to draw electricalenergy or power from a battery pack 237. The battery pack 237 can bemounted or fixedly coupled with the frame 12. The battery pack 237 canbe positioned rearward of the electric motor 236. The electric motor 236can be positioned on the frame 12 and/or coupled with the frame 12similarly to the engine 210.

The electric motor 236 can be configured to drive the power divider 220similarly to the engine 210 (e.g., through the power divider interface212 and the engine interface 222). The electric motor 236 can beconfigured to receive the electrical power from the battery pack(s) 237and output mechanical energy (e.g., torque) to the power divider 220. Inthis way, the electric motor 236 can be configured to drive the pumpsystem 140 through the pump clutch 232, and/or to drive the ETD 240through the ETD clutch 234. In some embodiments, the ETD clutch 234 isoptional for the fully-electric configuration of the hybrid powertrain200 shown in FIGS. 21 and 22 . The electric motor 236 can drive the ETD240 through the ETD clutch 234, which can in turn drive the front axle252 and/or the rear axle(s) 254. In this way, the electric motor 236 maydrive the front axle 252 and/or the rear axle(s) 254 for transportationof the fire fighting vehicle 10.

The battery pack(s) 237 that are used to power the electric motor 236can be the same as battery pack(s) 260. For example, both the ETD 240and the electric motor 236 may draw electrical energy from the samebattery pack (e.g., the battery pack 237 or the battery pack 260). Insome embodiments, the battery pack(s) 237 are separate from the batterypack(s) 260. The battery pack(s) 237 can be integrated with the batterypack(s) 260 so that the same batteries are used both to drive theelectric motor 236, and to drive the ETD 240, or are charged based onoperation of the ETD 240.

According to an exemplary embodiment, the battery pack 237, whichprovides electrical power to the electric motor 236, is a 330 kWhbattery pack. In other embodiments, the battery pack 237 has a larger orlesser capacity (e.g., at least 300 kWh, at least 350 kWh, 400 kWh,etc.). In some embodiments, a vehicle equipped with the full electricpowertrain as shown in FIGS. 21 and 22 is capable of accelerating from 0to 50 miles per hour in about 25 seconds or less. Advantageously, theelectric motor 236 and ETD 240 combination can be capable of providinglower-speed torque when compared to the systems with the engine 210. Theelectric motor 236 and ETD 240 combination may facilitate a fasterresponse/acceleration time of the fire fighting vehicle 10.Advantageously, the electric motor 236 and ETD 240 combination canreduce emissions that may be produced by the engine 210 and facilitatesa cleaner, more efficient, fire fighting vehicle.

It should be understood that the electric motor 236 can be used incombination with the ETD 240 or may be used without the ETD 240. Forexample, the ETD clutch 234 can directly drive the front axle 252 and/orthe rear axle(s) 254 directly without requiring the ETD 240.

In some embodiments, the full electric powertrain of FIGS. 21 and 22does not include the electric motor 236 and all components of thepowertrain (e.g., the pump system 140, the accessory drive 270, thefront axle(s) 252, the rear axle(s) 244, etc.) are driven solely by theETD 240. In such embodiments, the battery pack 237 may be directlycoupled to the ETD 240 to replace or supplement the battery pack 260.The pump system 140 and/or the vehicle accessories 290 may still bedriven through the power divider 220, however, but by the ETD 240 ratherthan by the electric motor 236. In some embodiments, the ETD clutch 234is positioned between the accessory drive 270 and the ETD 240 (e.g.,such that the ETD 240 can be selectively decoupled from the accessorydrive 270, etc.). In some embodiments, the power divider 220 does notinclude the ETD clutch 234. In some embodiments, the full electricpowertrain does not include the power divider 220, altogether. In suchembodiments, the pump system 140 and/or the vehicle accessories 290 maybe driven using one or more PTOs of the ETD 240 (e.g., PTO 241, etc.)and/or directly with the ETD shaft 230.

Independently Driven Pump System

Referring particularly to FIG. 23 , the hybrid powertrain 200 is shown,according to another embodiment. The hybrid powertrain 200 can includean additional primary mover, primary driver, engine, electric motor,pneumatic motor, hydraulic motor, etc., shown as pump mover 298. Pumpmover 298 may be mechanically coupled with the pump system 140 through apump mover interface 213. The pump mover 298 can be configured toindependently drive the pump system 140 without requiring input from theengine 210 and/or the electric motor 236 (e.g., if the electric motor236 is used in place of the engine 210). The pump mover 298 can beconfigured to draw electrical energy from a power source (e.g., anelectrical energy power source) if the pump mover 298 is an electricmotor. For example, the pump mover 298 may be configured to draw poweror electrical energy from the battery pack(s) 260, and/or the batterypack(s) 237. In some embodiments, an additional battery pack is includedwith the hybrid powertrain 200 (e.g., fixedly coupled with the frame 12)that is configured to provide the pump mover 298 with requiredelectrical energy/power.

If the pump system 140 is driven by a hydraulic system, the pump mover298 can be or include a fluid pump (e.g., a discharge pump) that isconfigured to receive hydraulic fluid from a fluid reservoir (e.g., atank, a fluid storage device, a reservoir, a container, etc.) andprovide pressurized fluid to a hydraulic motor. The hydraulic motor mayreceive the pressurized fluid and drive the pump system 140 to dischargethe fluid (e.g., the water). The pump mover 298 may drive the pumpclutch 232 and thereby drive the pump system 140. The pump clutch 232can be selectably transitionable (e.g., reconfigurable) between anengaged state and a disengaged state to selectively couple the pumpmover 298 with the pump system 140. The fluid pump used to pressurizethe fluid can be independently driven by an electric motor, an internalcombustion engine, etc. In other embodiments, the fluid pump (e.g., thepump mover 298) is driven by the engine 210 and/or the ETD 240 throughPTOs 241.

If the pump system 140 is driven by a pump mover 298 that is a pneumaticmotor (e.g., a rotary pneumatic motor, an air motor, etc.) the pumpmover 298 can be configured to receive a pressurized gas (e.g.,pressurized air) from a pressure vessel (e.g., a tank, an air storagedevice, a pressure vessel, etc.) that is coupled with the fire fightingvehicle 10 (e.g., fixedly coupled with the frame 12). The gas or airthat is stored in the pressure vessel may be pressurized with acompressor that is fluidly coupled with the pump mover 298. The pumpmover 298 may receive the pressurized air through one or more conduits,tubular members, pipes, etc., and outputs mechanical energy (e.g.,rotational kinetic energy) through the power divider interface 212. Thepump mover 298 can then independently drive the pump system 140 withoutrequiring input or operation of the engine 210 and/or the electric motor236.

Back-Driven Pump System

Referring particularly to FIG. 24 , the pump system 140 can be driven bythe ETD 240 (e.g., when the engine 210 is used in the hybrid powertrain200 and/or when the electric motor 236 is used in the hybrid powertrain200). The ETD 240 may be configured to drive the pump system 140 throughthe power divider 220. For example, the ETD 240 can draw electricalpower or energy from the battery pack 260 and operate to drive the ETDclutch 234 and the pump clutch 232, thereby driving the pump system 140.In some embodiments, the power divider 220 and/or the engine 210 includean engine clutch 235. The engine clutch 235 can be selectively engagedto selectively de-couple the engine 210 (or the electric motor 236) fromthe power divider 220. When the ETD 240 is used to drive the pump system140 through the power divider 220, the engine clutch 235 may beselectively de-coupled from the power divider 220 so that the pumpsystem 140 can be driven without driving the engine 210.

In some embodiments, the pump system 140 is back-driven by the ETD 240through the power divider 220 for lower power pump applications (e.g.,for applications where a lower discharge rate of fluid is required). Forexample, if a lower discharge rate of the fluid is required by the pumpsystem 140, the pump system 140 may require a lower power input. Forapplications which require a power input at or below a particular level,the ETD 240 can be used to drive the pump system 140 (e.g., through thepower divider 220). Advantageously, this reduces the need to drive thepump system 140 with the engine 210, which may be less efficient thanusing the ETD 240. Additionally, using the ETD 240 to drive the pumpsystem 140 can reduce emissions which may be produced by the engine 210.For higher hp applications of the pump system 140, the pump system 140may be driven by the engine 210 (or the electric motor 236).

In other embodiments, the pump system 140 is driven by the ETD 240through a PTO 241. The PTO 241 can be rotatably coupled with an input oran output shaft (e.g., ETD shaft 230) of the ETD 240. The ETD 240 maydrive the pump system 140 through the PTO 241, without requiring drivingof the power divider 220. For example, the PTO 241 may include or berotatably fixedly coupled with a clutch 243 that is configured toselectively engage the ETD shaft 230 (e.g., in response to receiving acommand from a controller) and thereby couple the pump shaft 228 withthe ETD shaft 230 through the PTO 241.

Genset Configuration

Referring particularly to FIG. 25 , the hybrid powertrain 200 mayinclude a genset system, etc., shown as generator system 256. Thegenerator system 256 can include a generator, a mechanical transducer,an energy conversion device, an electrical generator, etc., shown asgenerator 238. The generator 238 may be driven by the engine 210 througha generator interface 215. In some embodiments, the generator interface215 is the same as or similar to the power divider interface 212. Thegenerator 238 receives mechanical energy (e.g., torque, rotationalkinetic energy, etc.) from the engine 210 and generates electricalenergy (e.g., electrical power) using the mechanical energy. Thegenerator 238 can output the electrical power to the battery pack(s) 260and/or the ETD 240. For example, some or all of the electrical powergenerated by the generator 238 may be provided to the battery pack(s)260, where it may be stored and later used by the ETD 240 to drive anyof the front axle 252, the rear axle 254, or the accessory drive 270.

Some or all of the electrical power generated by the generator 238 mayalso be provided directly to the ETD 240 which uses the electrical powerto drive any of the front axle 252, the rear axle 254, or the accessorydrive 270. In some embodiments, the ETD 240 is configured to draw arequired amount of electrical power from the generator 238, and excesselectrical power that is generated by the generator 238 is provided tothe battery pack(s) 260 where it is stored for later use. If the hybridpowertrain 200 includes the generator system 256, the pump system 140may be driven by an independent mover or an independent drive system,shown as pump mover 298. The pump mover 298 may be an electric motor, aninternal combustion engine, etc., or any other primary mover that isconfigured to output mechanical energy to drive pump system 140. In someembodiments, the pump mover 298 is configured to receive electricalpower (e.g., electrical energy) from the generator 238 and/or thebattery pack(s) 260.

In-Line Configuration with ETD

Referring to FIG. 26 , the hybrid powertrain 200 is shown, according toanother embodiment. In this embodiment, the engine 210, the ETD 240, andthe pump system 140 are positioned in an in-line configuration. Theengine 210, the ETD 240, and the pump system 140 are arranged in serieswith one another. Specifically, the ETD 240 is positioned between theengine 210 and the pump system 140 such that the engine 210 may drivethe pump system 140 through the ETD 240.

As shown in FIG. 26 , the engine 210 includes a first interface, shownas clutch interface 1000, coupled to a first shaft, shown as engineshaft 1002. The ETD 240 includes a second interface, shown as clutchinterface 1004, coupled to a second shaft, shown as electric motor(“EM”) shaft 1006. A first clutch or neutral clutch, shown as engineclutch 1008, is coupled to the engine shaft 1002 and the EM shaft 1006.The engine clutch 1008 may selectively couple the engine shaft 1002 tothe EM shaft 1006 in response to a signal from a controller (e.g., thecontroller 510). When engaged, the engine clutch 1008 couples the engine210 to the ETD 240, transferring rotational mechanical energy betweenthe engine 210 and the ETD 240. The EM shaft 1006 has a third interface,shown as pulley interface 1010. The pulley interface 1010 couples the EMshaft 1006 to the accessory drive 270.

A second clutch or PTO clutch, shown as pump clutch 1020, is positionedbetween the ETD 240 and the pump system 140. The pump clutch 1020 mayselectively couple the PTO 241 to the pump system 140 in response to asignal from a controller (e.g., the controller 510). When engaged, thepump clutch 1020 couples the ETD 240 to the pump system 140,transferring rotational mechanical energy between the ETD 240 and thepump system 140.

The hybrid powertrain 200 of FIG. 26 may be selectively reconfiguredbetween different modes of operation by engaging or disengaging theengine clutch 1008 and/or the pump clutch 1020. In some embodiments, theEM shaft 1006 directly couples the accessory drive 270 to the ETD 240such that the accessory drive 270 is coupled to the ETD 240 regardlessof whether or not the engine clutch 1008 and the pump clutch 1020 areengaged (e.g., in all modes of operation). When the engine clutch 1008is engaged, the engine 210 is coupled to the ETD 240. The engine 210 mayprovide rotational mechanical energy to drive the ETD 240 (e.g., toproduce electrical energy, to drive the front axle 252 and/or the rearaxle 254, to drive the accessory drive 270). The ETD 240 may providerotational mechanical energy to the engine 210 (e.g., to start theengine 210). When the pump clutch 1020 is engaged, the ETD 240 iscoupled to the pump system 140. The ETD 240 may provide rotationalmechanical energy to drive the pump system 140. When both the engineclutch 1008 and the pump clutch 1020 are engaged, the ETD 240, theengine 210, and the pump system 140 are coupled to one another. Theengine 210 may provide rotational mechanical energy to drive the pumpsystem 140.

Referring to FIGS. 27-34 , an arrangement of the hybrid powertrain 200of FIG. 26 is shown according to an exemplary embodiment. As shown, theengine 210 is coupled to the accessory drive 270. Specifically, theengine 210 is directly coupled to an accessory base 272 that supportsthe vehicle accessories 290 and the accessory pulley assembly 274. TheEM shaft 1006 extends through the accessory drive 270 (e.g., to coupleto the ETD 240).

As shown in FIGS. 28 and 29 , a distal end of the engine shaft 1002includes a disc-shaped portion, shown as hub 1030. The hub 1030 isdirectly, fixedly coupled (e.g., fastened) to the engine clutch 1008.The EM shaft 1006 extends through the engine clutch 1008 such that adistal end of the EM shaft 1006 is positioned adjacent the hub 1030. Abearing 1032 pivotally couples the hub 1030 to the distal end of the EMshaft 1006. The bearing 1032 may support the EM shaft 1006 whilemaintaining alignment between the engine shaft 1002 and the EM shaft1006. The EM shaft 1006 is fixedly coupled to the engine clutch 1008(e.g., an outer surface of the EM shaft 1006 may be fixedly coupled toan inner surface of the engine clutch 1008). In some embodiments, theengine clutch 1008 includes a series of plates that are pressed againstone another (e.g., by the application of pressurized hydraulic fluid) toengage the engine clutch 1008 and couple the engine shaft 1002 to the EMshaft 1006. The EM shaft 1006 extends through and is fixedly coupled tothe drive pulley 280. A proximal end of the EM shaft 1006 is coupled tothe ETD 240 (e.g., through a universal joint).

Referring to FIGS. 30-34 , the accessory pulley assembly 274 is shownaccording to an exemplary embodiment. The accessory pulley assembly 274couples the EM shaft 1006 to the vehicle accessories 290. Because theaccessory drive 270 is coupled to the EM shaft 1006, all of the vehicleaccessories 290 can be driven in any mode of operation of the firefighting vehicle 10. By way of example, the vehicle accessories 290 maybe driven by the engine 210 (e.g., when the engine clutch 1008 isengaged), even if the ETD 240 is not operating. By way of anotherexample, the vehicle accessories 290 may be driven by the ETD 240, evenif the engine 210 is turned off or the engine clutch 1008 is disengaged.This arrangement facilitates flexibility in operation withoutsacrificing the functionality of the vehicle accessories 290.

In the embodiment shown in FIGS. 30-34 , the vehicle accessories 290include an alternator 292 (e.g. an electrical energy generator), an airconditioning compressor 294, a chassis air compressor 296, and a pump,shown as oil pump 299, all of which are driven by the EM shaft 1006through the accessory pulley assembly 274. The alternator 292 receivesrotational mechanical energy and produces electrical energy (e.g., ACelectrical energy, DC electrical energy). The produced electrical energymay power one or more electrical loads within the fire fighting vehicle10 (e.g., lights, electric motors, the controller 510, batteries,capacitors, etc.) that are electrically coupled to the alternator 292.The air conditioning compressor 294 receives rotational mechanicalenergy and provides a flow of compressed refrigerant (i.e., a flow ofpressurized fluid or fluid energy). The compressed refrigerant may beused within a heating, ventilation, and air conditioning (“HVAC”) systemof the fire fighting vehicle 10. Specifically, the compressedrefrigerant may be used in a refrigeration circuit that provides cooledair to the front cabin 20 to improve the comfort of one or moreoperators. The chassis air compressor 296 receives rotational mechanicalenergy and provides a flow of compressed air (i.e., a flow ofpressurized fluid or fluid energy). The compressed air may be used byone or more systems of the fire fighting vehicle 10 (e.g., air brakes, asuspension, etc.) that are fluidly coupled to the chassis air compressor296. The oil pump 299 receives rotational mechanical energy and providesa flow of pressurized oil (i.e., a flow of pressurized fluid or fluidenergy). The pressurized oil may be used to lubricate one or morecomponents of the fire fighting vehicle 10 (e.g., the engine 210, thepump system 140, the ETD 240, etc.) that are fluidly coupled to the oilpump 299.

The vehicle accessories 290 are coupled to and supported by theaccessory base 272. The accessory pulley assembly 274 includes a drivepulley 280 that is fixedly coupled to the EM shaft 1006. As shown inFIG. 28 , the EM shaft 1006 extends through the center of the drivepulley 280. The alternator 292 is coupled to a first pulley, shown asalternator pulley 1140. The air conditioning compressor 294 is coupledto a second pulley, shown as air conditioning compressor pulley 1142.The chassis air compressor 296 and the oil pump 299 are aligned with oneanother and both coupled to a third pulley, shown as oil pump pulley1144. A series of fourth pulleys, shown as idler pulleys 1146, arepivotally coupled to the accessory base 272. The idler pulleys 1146 arefree to rotate relative to the accessory base 272 and facilitate routingof the accessory belt 278 to maintain sufficient wrap around each of thealternator pulley 1140, the air conditioning compressor pulley 1142, andthe oil pump pulley 1144 to ensure effective power transfer. One of theidler pulleys 1146 is indirectly coupled to the accessory base 272 by anarm, shown as tensioner 1148. The tensioner 1148 is biased (e.g., by atorsion spring) to rotate in a direction (e.g., counter-clockwise asshown in FIG. 34 ) that forces the corresponding idler pulley 1146against the accessory belt 278 to maintain tension on the accessory belt278. The accessory belt 278 wraps in a serpentine pattern around thedrive pulley 280, the alternator pulley 1140, the air conditioningcompressor pulley 1142, the oil pump pulley 1144, and the idler pulleys1146. During operation of the accessory drive 270, the accessory belt278 transfers rotational mechanical energy from the drive pulley 280 tothe alternator pulley 1140, the air conditioning compressor pulley 1142,and the oil pump pulley 1144 to drive each of the correspondingaccessories. A sensor (e.g., a Hall effect sensor), shown as speedsensor 1150, is coupled to the accessory base 272 proximate the drivepulley 280. The speed sensor 1150 measures a rotational speed of thedrive pulley 280. The speed sensor 1150 may provide the measured speedto a controller (e.g., the controller 510).

In-Line Configuration with Electric Drive Module

Referring to FIG. 35 , the hybrid powertrain 200 is shown, according toanother embodiment. The embodiment of FIG. 35 may be substantiallysimilar to the embodiment of FIG. 26 except as otherwise specified. Inthis embodiment, the ETD 240 is replaced with an electric axle orelectric drive assembly, shown as electric drive module 1100. Theelectric drive module 1100 is configured to propel the fire fightingvehicle 10. The electric drive module 1100 may include the front axle252 and/or the rear axle 254. The electric drive module 1100 may be aself-contained subassembly including a housing 1101 that at leastpartially contains all of the components of the electric drive module1100. In some embodiments, the fire fighting vehicle 10 includesmultiple electric drive modules 1100, each containing a different axle.

The electric drive module 1100 includes a primary driver or electricmotor/generator, shown as electric motor 1102. The electric motor 1102is configured to receive electrical energy (e.g., from the battery pack260, from the battery pack 237) and provides rotational mechanicalenergy. Operation of the electric motor 1102 may be controlled by acontroller (e.g., the controller 510). As shown, the electric motor 1102is electrically coupled to the battery pack 260.

The electric drive module 1100 further includes a power transmissiondevice or gearbox, shown as transmission 1104. The transmission 1104 iscoupled to the front axle 252 and/or the rear axle 254. The transmission1104 is further coupled to the EM shaft 1106 by an interface, shown asPTO 1110. The transmission 1104 is configured to receive rotationalmechanical energy and transfer the rotational mechanical energy to oneor more outputs. (e.g., the front axle 252, the rear axle 254, the PTO1110, etc.). The transmission 1104 may be configured to vary a ratiobetween an input speed (e.g., from the electric motor 1102, etc.) and anoutput speed (e.g., of the front axle, etc.). Operation of thetransmission 1104 may be controlled by a controller (e.g., thecontroller 510). Further, the electric drive module 1100 may replace theETD 240 in any of the embodiments disclosed herein.

Other Alternative Configurations

Referring generally to FIGS. 21-35 , the hybrid powertrain 200 may alsobe configured as a diesel-hydraulic system, a diesel-pneumatic system,an electric-hydraulic, and/or an electric-pneumatic system. For example,a first or primary mover (e.g., the engine 210) that is configured todrive the hybrid powertrain 200 may be an electric motor (e.g., theelectric motor 236), or may be a diesel engine (e.g., the engine 210).The pump system 140 can be a hydraulic system and/or a pneumatic system.In this way, the hybrid powertrain 200 may be configured as anycombination of the first mover and the pump system 140 such as adiesel-hydraulic powertrain, a diesel-pneumatic powertrain, anelectric-hydraulic powertrain, and/or an electric-pneumatic powertrain.

As utilized herein, the terms “approximately,” “about,” “substantially”,and similar terms are intended to have a broad meaning in harmony withthe common and accepted usage by those of ordinary skill in the art towhich the subject matter of this disclosure pertains. It should beunderstood by those of skill in the art who review this disclosure thatthese terms are intended to allow a description of certain featuresdescribed and claimed without restricting the scope of these features tothe precise numerical ranges provided. Accordingly, these terms shouldbe interpreted as indicating that insubstantial or inconsequentialmodifications or alterations of the subject matter described and claimedare considered to be within the scope of the disclosure as recited inthe appended claims.

It should be noted that the term “exemplary” and variations thereof, asused herein to describe various embodiments, are intended to indicatethat such embodiments are possible examples, representations, orillustrations of possible embodiments (and such terms are not intendedto connote that such embodiments are necessarily extraordinary orsuperlative examples).

The term “coupled” and variations thereof, as used herein, means thejoining of two members directly or indirectly to one another. Suchjoining may be stationary (e.g., permanent or fixed) or moveable (e.g.,removable or releasable). Such joining may be achieved with the twomembers coupled directly to each other, with the two members coupled toeach other using a separate intervening member and any additionalintermediate members coupled with one another, or with the two memberscoupled to each other using an intervening member that is integrallyformed as a single unitary body with one of the two members. If“coupled” or variations thereof are modified by an additional term(e.g., directly coupled), the generic definition of “coupled” providedabove is modified by the plain language meaning of the additional term(e.g., “directly coupled” means the joining of two members without anyseparate intervening member), resulting in a narrower definition thanthe generic definition of “coupled” provided above. Such coupling may bemechanical, electrical, or fluidic.

References herein to the positions of elements (e.g., “top,” “bottom,”“above,” “below”) are merely used to describe the orientation of variouselements in the figures. It should be noted that the orientation ofvarious elements may differ according to other exemplary embodiments,and that such variations are intended to be encompassed by the presentdisclosure.

The hardware and data processing components used to implement thevarious processes, operations, illustrative logics, logical blocks,modules and circuits described in connection with the embodimentsdisclosed herein may be implemented or performed with a general purposesingle- or multi-chip processor, a digital signal processor (DSP), anapplication specific integrated circuit (ASIC), a field programmablegate array (FPGA), or other programmable logic device, discrete gate ortransistor logic, discrete hardware components, or any combinationthereof designed to perform the functions described herein. A generalpurpose processor may be a microprocessor, or, any conventionalprocessor, controller, microcontroller, or state machine. A processoralso may be implemented as a combination of computing devices, such as acombination of a DSP and a microprocessor, a plurality ofmicroprocessors, one or more microprocessors in conjunction with a DSPcore, or any other such configuration. In some embodiments, particularprocesses and methods may be performed by circuitry that is specific toa given function. The memory (e.g., memory, memory unit, storage device)may include one or more devices (e.g., RAM, ROM, Flash memory, hard diskstorage) for storing data and/or computer code for completing orfacilitating the various processes, layers and modules described in thepresent disclosure. The memory may be or include volatile memory ornon-volatile memory, and may include database components, object codecomponents, script components, or any other type of informationstructure for supporting the various activities and informationstructures described in the present disclosure. According to anexemplary embodiment, the memory is communicably connected to theprocessor via a processing circuit and includes computer code forexecuting (e.g., by the processing circuit or the processor) the one ormore processes described herein.

The present disclosure contemplates methods, systems and programproducts on any machine-readable media for accomplishing variousoperations. The embodiments of the present disclosure may be implementedusing existing computer processors, or by a special purpose computerprocessor for an appropriate system, incorporated for this or anotherpurpose, or by a hardwired system. Embodiments within the scope of thepresent disclosure include program products comprising machine-readablemedia for carrying or having machine-executable instructions or datastructures stored thereon. Such machine-readable media can be anyavailable media that can be accessed by a general purpose or specialpurpose computer or other machine with a processor. By way of example,such machine-readable media can comprise RAM, ROM, EPROM, EEPROM, orother optical disk storage, magnetic disk storage or other magneticstorage devices, or any other medium which can be used to carry or storedesired program code in the form of machine-executable instructions ordata structures and which can be accessed by a general purpose orspecial purpose computer or other machine with a processor. Combinationsof the above are also included within the scope of machine-readablemedia. Machine-executable instructions include, for example,instructions and data which cause a general purpose computer, specialpurpose computer, or special purpose processing machines to perform acertain function or group of functions.

Although the figures and description may illustrate a specific order ofmethod steps, the order of such steps may differ from what is depictedand described, unless specified differently above. Also, two or moresteps may be performed concurrently or with partial concurrence, unlessspecified differently above. Such variation may depend, for example, onthe software and hardware systems chosen and on designer choice. Allsuch variations are within the scope of the disclosure. Likewise,software implementations of the described methods could be accomplishedwith standard programming techniques with rule-based logic and otherlogic to accomplish the various connection steps, processing steps,comparison steps, and decision steps.

It is important to note that the construction and arrangement of thefire fighting vehicle 10 and the systems and components thereof as shownin the various exemplary embodiments is illustrative only. Additionally,any element disclosed in one embodiment may be incorporated or utilizedwith any other embodiment disclosed herein. Although only one example ofan element from one embodiment that can be incorporated or utilized inanother embodiment has been described above, it should be appreciatedthat other elements of the various embodiments may be incorporated orutilized with any of the other embodiments disclosed herein.

1. An electrified fire fighting vehicle comprising: a powertrainincluding: a battery pack; an electromagnetic device; and an engine; anda controller configured to: monitor a state-of-charge of the batterypack; operate the electromagnetic device using stored energy in thebattery pack to provide a performance condition including (i)accelerating the electrified fire fighting vehicle to a driving speed ofat least 50 miles-per-hour in an acceleration time and (ii) maintainingor exceeding the driving speed for a period of time, wherein theacceleration time is 30 second or less, and wherein an aggregate of theacceleration time and the period of time is at least 3 minutes; andstart and operate the engine in response to a start condition tofacilitate reserving sufficient stored energy in the battery pack suchthat the state-of-charge is maintained above a minimum state-of-chargethreshold that is sufficient to facilitate the performance condition,wherein the start condition includes at least one of (i) the minimumstate-of-charge threshold being reached or (ii) receiving a startcommand from an operator.
 2. The electrified fire fighting vehicle ofclaim 1, wherein the electrified fire fighting vehicle is an airportrescue fire fighting (ARFF) vehicle having a water tank with a watercapacity of at least 1,500 gallons and an agent tank with an agentcapacity of at least 150 gallons, wherein the performance conditionincludes (i) accelerating the electrified fire fighting vehicle to thedriving speed of at least 50 miles-per-hour in the acceleration time and(ii) maintaining or exceeding the driving speed for the period of timewith the water tank at a maximum water capacity and the agent tank at amaximum agent capacity.
 3. The electrified fire fighting vehicle ofclaim 1, wherein the start condition includes (i) the minimumstate-of-charge threshold being reached and (ii) receiving the startcommand from the operator.
 4. The electrified fire fighting vehicle ofclaim 1, wherein the controller is configured to prevent charging thebattery pack above a maximum state-of-charge threshold that is less than100% state-of-charge to prevent accelerated degradation of astate-of-health of the battery pack.
 5. The electrified fire fightingvehicle of claim 4, wherein the controller configured to adaptivelyreduce the maximum state-of-charge threshold as the state-of-health ofthe battery pack degrades.
 6. The electrified fire fighting vehicle ofclaim 1, wherein the controller is configured to: monitor a temperatureof the battery pack; and prevent the temperature from exceeding atemperature threshold to prevent accelerated degradation of astate-of-health of the battery pack.
 7. The electrified fire fightingvehicle of claim 1, wherein the controller is configured to: monitor adepth-of-discharge of the battery pack during a discharge event; andprevent the depth-of-discharge from exceeding a depth-of-dischargethreshold to prevent accelerated degradation of a state-of-health of thebattery pack.
 8. The electrified fire fighting vehicle of claim 7,wherein the controller is configured to adaptively adjust thedepth-of-discharge threshold such that the state-of-charge can befurther depleted during discharge events as the battery pack degrades.9. An electrified airport rescue fire fighting (ARFF) vehiclecomprising: a chassis; a front axle; a rear axle; a water tank having amaximum water capacity of at least 1,000 gallons; an agent tank having amaximum agent capacity of at least 150 gallons; a battery pack; and anelectromagnetic device electrically coupled to the battery pack, theelectromagnetic device configured to drive at least one of the frontaxle or the rear axle; wherein the battery pack has a battery capacitysufficient to power the electromagnetic device to facilitate (i)accelerating the electrified ARFF vehicle to a driving speed of at least50 miles-per-hour in an acceleration time and (ii) maintaining orexceeding the driving speed for a period of time while the water tank isat the maximum water capacity and the agent tank is at the maximum agentcapacity; wherein the acceleration time is 30 second or less; andwherein an aggregate of the acceleration time and the period of time isat least 3 minutes.
 10. The electrified ARFF vehicle of claim 9, whereinthe maximum water capacity is at least 1,500 gallons.
 11. Theelectrified ARFF vehicle of claim 9, wherein the rear axle includes apair of rear axles.
 12. The electrified ARFF vehicle of claim 11,wherein the maximum water capacity is at least 3,000 gallons.
 13. Theelectrified ARFF vehicle of claim 9, wherein the acceleration time is 28seconds or less.
 14. The electrified ARFF vehicle of claim 13, whereinthe acceleration time is 25 seconds or less.
 15. The electrified ARFFvehicle of claim 9, further comprising: an engine; and a controllerconfigured to: monitor a state-of-charge of the battery pack; operatethe electromagnetic device using stored energy in the battery pack toprovide a performance condition including (i) accelerating theelectrified ARFF vehicle to the driving speed of at least 50miles-per-hour in the acceleration time and (ii) maintaining orexceeding the driving speed for the period of time; and start andoperate the engine in response to a start condition to facilitatereserving sufficient stored energy in the battery pack such that thestate-of-charge is maintained above a minimum state-of-charge thresholdthat is sufficient to facilitate the performance condition, wherein thestart condition includes at least one of (i) the minimum state-of-chargethreshold being reached or (ii) receiving a start command from anoperator.
 16. The electrified ARFF vehicle of claim 9, wherein theelectromagnetic device includes a first electric motor and a secondelectric motor.
 17. The electrified ARFF vehicle of claim 9, furthercomprising a genset including an engine and a generator driven by theengine to produce electrical energy that is provided to at least one ofthe battery pack or the electromagnetic device.
 18. The electrified ARFFvehicle of claim 9, further comprising a pump configured to providewater from the water tank and agent from the agent tank to a fluidoutlet of the electrified ARFF vehicle.
 19. An electrified vehiclecomprising: a chassis; a front axle coupled to the chassis; a rear axlecoupled to the chassis; a battery pack; an electromagnetic deviceelectrically coupled to the battery pack, the electromagnetic deviceconfigured to drive at least one of the front axle or the rear axle; anda controller configured to: monitor a state-of-charge of the batterypack; monitor a temperature of the battery pack; monitor adepth-of-discharge of the battery pack during discharge events; prevent(i) charging the battery pack above a maximum state-of-charge thresholdthat is less than 100% state-of-charge, (ii) prevent thedepth-of-discharge from exceeding a depth-of-discharge threshold, and(iii) prevent the temperature from exceeding a temperature threshold toprevent accelerated degradation of a state-of-health of the batterypack; adaptively reduce the maximum state-of-charge threshold as thestate-of-health of the battery pack degrades; and adaptively adjust thedepth-of-discharge threshold such that the state-of-charge can befurther depleted during subsequent discharge events as the battery packdegrades.
 20. The electrified vehicle of claim 19, wherein theelectrified vehicle is a municipal fire fighting vehicle or an airportrescue fire fighting (ARFF) vehicle.